Add dark mode override for non-native DevExpress themes

Implements a dark mode override system for DevExpress Blazor themes lacking native dark support. Adds a JS function to toggle a dx-dark class on <html>, updates ThemeState to detect native dark themes, and applies targeted CSS variable overrides for consistent dark styling. Disables prerendering to ensure JS interop, and improves theme switching logic and documentation.
Remove unused menu state and toggle logic from NavMenu
2026-05-05 16:41:15 +02:00 · 2026-04-30 15:41:05 +02:00 · 2026-04-30 15:37:04 +02:00 · 2026-04-23 15:59:50 +02:00 · 2026-04-23 15:44:26 +02:00 · 2026-04-23 13:55:05 +02:00
129 changed files with 2913 additions and 5050 deletions
--- a/DbFirst.API/Controllers/CatalogsController.cs
+++ b/DbFirst.API/Controllers/CatalogsController.cs
@@ -1,7 +1,7 @@
-using DbFirst.Application.Catalogs;
+
 using DbFirst.Application.Catalogs.Commands;
 using DbFirst.Application.Catalogs.Queries;
-using DbFirst.Domain;
+using DbFirst.Contracts.Catalogs;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;

@@ -37,7 +37,7 @@ public class CatalogsController : ControllerBase
    }

    [HttpPost]
-    public async Task<ActionResult<CatalogReadDto>> Create(CatalogWriteDto dto, CancellationToken cancellationToken)
+    public async Task<ActionResult<CatalogReadDto>> Create([FromBody]CatalogWriteDto dto, CancellationToken cancellationToken)
    {
        var created = await _mediator.Send(new CreateCatalogCommand(dto), cancellationToken);
        if (created == null)
@@ -48,19 +48,8 @@ public class CatalogsController : ControllerBase
    }

    [HttpPut("{id:int}")]
-    public async Task<ActionResult<CatalogReadDto>> Update(int id, CatalogWriteDto dto, CancellationToken cancellationToken)
+    public async Task<ActionResult<CatalogReadDto>> Update(int id, [FromBody] CatalogWriteDto dto, CancellationToken cancellationToken)
    {
-        var current = await _mediator.Send(new GetCatalogByIdQuery(id), cancellationToken);
-        if (current == null)
-        {
-            return NotFound();
-        }
-        if (dto.UpdateProcedure == CatalogUpdateProcedure.Update &&
-            !string.Equals(current.CatTitle, dto.CatTitle, StringComparison.OrdinalIgnoreCase))
-        {
-            return BadRequest("Titel kann nicht geändert werden.");
-        }
-
        var updated = await _mediator.Send(new UpdateCatalogCommand(id, dto), cancellationToken);
        if (updated == null)
        {
--- a/DbFirst.API/Controllers/LayoutsController.cs
+++ b/DbFirst.API/Controllers/LayoutsController.cs
@@ -1,7 +1,8 @@
-using System.Text;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.Layouts;
 using DbFirst.Domain.Entities;
 using Microsoft.AspNetCore.Mvc;
+using System.Text;

 namespace DbFirst.API.Controllers;

@@ -83,12 +84,4 @@ public class LayoutsController : ControllerBase
            LayoutData = layoutData
        };
    }
-
-    public sealed class LayoutDto
-    {
-        public string LayoutType { get; set; } = string.Empty;
-        public string LayoutKey { get; set; } = string.Empty;
-        public string UserName { get; set; } = string.Empty;
-        public string LayoutData { get; set; } = string.Empty;
-    }
 }
--- a/DbFirst.API/Controllers/MassDataController.cs
+++ b/DbFirst.API/Controllers/MassDataController.cs
@@ -1,6 +1,6 @@
-using DbFirst.Application.MassData;
 using DbFirst.Application.MassData.Commands;
 using DbFirst.Application.MassData.Queries;
+using DbFirst.Contracts.MassData;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;

@@ -50,7 +50,7 @@ public class MassDataController : ControllerBase
    }

    [HttpPost("upsert")]
-    public async Task<ActionResult<MassDataReadDto>> Upsert(MassDataWriteDto dto, CancellationToken cancellationToken)
+    public async Task<ActionResult<MassDataReadDto>> Upsert([FromBody]MassDataWriteDto dto, CancellationToken cancellationToken)
    {
        var result = await _mediator.Send(new UpsertMassDataByCustomerNameCommand(dto), cancellationToken);
        return Ok(result);
--- a/DbFirst.API/Dashboards/DashboardChangeNotifier.cs
+++ b/DbFirst.API/Dashboards/DashboardChangeNotifier.cs
@@ -6,14 +6,23 @@ namespace DbFirst.API.Dashboards;
 public class DashboardChangeNotifier : IDashboardChangeNotifier
 {
    private readonly IHubContext<DashboardsHub> _hubContext;
+    private readonly ILogger<DashboardChangeNotifier> _logger;

-    public DashboardChangeNotifier(IHubContext<DashboardsHub> hubContext)
+    public DashboardChangeNotifier(IHubContext<DashboardsHub> hubContext, ILogger<DashboardChangeNotifier> logger)
    {
        _hubContext = hubContext;
+        _logger = logger;
    }

-    public void NotifyChanged()
+    public async Task NotifyChangedAsync()
    {
-        _ = _hubContext.Clients.All.SendAsync("DashboardsChanged");
+        try
+        {
+            await _hubContext.Clients.All.SendAsync("DashboardsChanged");
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Failed to notify dashboard clients.");
+        }
    }
 }
--- a/DbFirst.API/Dashboards/DashboardConfiguratorFactory.cs
+++ b/DbFirst.API/Dashboards/DashboardConfiguratorFactory.cs
@@ -0,0 +1,115 @@
+using DbFirst.Domain.Entities;
+using DevExpress.DashboardCommon;
+using DevExpress.DashboardWeb;
+using DevExpress.DataAccess.Json;
+using System.Xml.Linq;
+
+namespace DbFirst.API.Dashboards;
+
+public static class DashboardConfiguratorFactory
+{
+    public static DashboardConfigurator Create(
+        IServiceProvider serviceProvider,
+        IConfiguration configuration,
+        IWebHostEnvironment environment)
+    {
+        // Den gesamten Inhalt des Lambdas hierher verschieben
+        // serviceProvider, configuration, environment statt builder.* verwenden
+
+        var dashboardsPath = Path.Combine(environment.ContentRootPath, "Data", "Dashboards");
+        Directory.CreateDirectory(dashboardsPath);
+
+        var defaultDashboardPath = Path.Combine(dashboardsPath, "DefaultDashboard.xml");
+        if (!File.Exists(defaultDashboardPath))
+        {
+            var defaultDashboard = new Dashboard();
+            defaultDashboard.Title.Text = "Default Dashboard";
+            defaultDashboard.SaveToXml(defaultDashboardPath);
+        }
+
+        var dashboardBaseUrl = configuration["Dashboard:BaseUrl"]
+            ?? configuration["ApiBaseUrl"]
+            ?? configuration["ASPNETCORE_URLS"]?.Split(';', StringSplitOptions.RemoveEmptyEntries).FirstOrDefault()
+            ?? "https://localhost:7204";
+
+        dashboardBaseUrl = dashboardBaseUrl.TrimEnd('/');
+
+        var catalogsGridDashboardPath = Path.Combine(dashboardsPath, "CatalogsGrid.xml");
+        if (!File.Exists(catalogsGridDashboardPath))
+        {
+            var dashboard = new Dashboard();
+            dashboard.Title.Text = "Catalogs (Dashboard Grid)";
+
+            var catalogDataSource = new DashboardJsonDataSource("Catalogs (API)")
+            {
+                ComponentName = "catalogsDataSource",
+                JsonSource = new UriJsonSource(new Uri($"{dashboardBaseUrl}/api/catalogs"))
+            };
+
+            dashboard.DataSources.Add(catalogDataSource);
+
+            var grid = new GridDashboardItem
+            {
+                DataSource = catalogDataSource,
+                Name = "Catalogs"
+            };
+
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.Guid))) { Name = "Id" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.CatTitle))) { Name = "Titel" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.CatString))) { Name = "String" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.AddedWho))) { Name = "Angelegt von" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.AddedWhen))) { Name = "Angelegt am" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.ChangedWho))) { Name = "Geändert von" });
+            grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.ChangedWhen))) { Name = "Geändert am" });
+
+            dashboard.Items.Add(grid);
+
+            var layoutGroup = new DashboardLayoutGroup { Orientation = DashboardLayoutGroupOrientation.Vertical };
+            layoutGroup.ChildNodes.Add(new DashboardLayoutItem(grid));
+            dashboard.LayoutRoot = layoutGroup;
+
+            dashboard.SaveToXml(catalogsGridDashboardPath);
+        }
+
+        DashboardConfigurator configurator = new DashboardConfigurator();
+
+        var connectionString = configuration.GetConnectionString("DefaultConnection") ?? string.Empty;
+        var notifier = serviceProvider.GetRequiredService<IDashboardChangeNotifier>();
+        var dashboardStorage = new SqlDashboardStorage(connectionString, "TBDD_SMF_CONFIG", notifier: notifier);
+        configurator.SetDashboardStorage(dashboardStorage);
+
+        DataSourceInMemoryStorage dataSourceStorage = new DataSourceInMemoryStorage();
+        DashboardJsonDataSource jsonDataSourceUrl = new DashboardJsonDataSource("JSON Data Source (URL)");
+        jsonDataSourceUrl.JsonSource = new UriJsonSource(
+                new Uri("https://raw.githubusercontent.com/DevExpress-Examples/DataSources/master/JSON/customers.json"));
+        jsonDataSourceUrl.RootElement = "Customers";
+        dataSourceStorage.RegisterDataSource("jsonDataSourceUrl", jsonDataSourceUrl.SaveToXml());
+
+        var catalogsJsonDataSource = new DashboardJsonDataSource("Catalogs (API)")
+        {
+            ComponentName = "catalogsDataSource",
+            JsonSource = new UriJsonSource(new Uri($"{dashboardBaseUrl}/api/catalogs"))
+        };
+        dataSourceStorage.RegisterDataSource(catalogsJsonDataSource.ComponentName, catalogsJsonDataSource.SaveToXml());
+        dataSourceStorage.RegisterDataSource(catalogsJsonDataSource.Name, catalogsJsonDataSource.SaveToXml());
+
+        configurator.SetDataSourceStorage(dataSourceStorage);
+
+        EnsureDashboardInStorage(dashboardStorage, "DefaultDashboard", defaultDashboardPath);
+        EnsureDashboardInStorage(dashboardStorage, "CatalogsGrid", catalogsGridDashboardPath);
+
+        return configurator;
+    }
+
+    private static void EnsureDashboardInStorage(IEditableDashboardStorage storage, string id, string filePath)
+    {
+        var exists = storage.GetAvailableDashboardsInfo().Any(info => string.Equals(info.ID, id, StringComparison.OrdinalIgnoreCase));
+        if (exists || !File.Exists(filePath))
+        {
+            return;
+        }
+
+        var doc = XDocument.Load(filePath);
+        storage.AddDashboard(doc, id);
+    }
+}
--- a/DbFirst.API/Dashboards/IDashboardChangeNotifier.cs
+++ b/DbFirst.API/Dashboards/IDashboardChangeNotifier.cs
@@ -2,5 +2,5 @@ namespace DbFirst.API.Dashboards;

 public interface IDashboardChangeNotifier
 {
-    void NotifyChanged();
+    Task NotifyChangedAsync();
 }
--- a/DbFirst.API/Dashboards/SqlDashboardStorage.cs
+++ b/DbFirst.API/Dashboards/SqlDashboardStorage.cs
@@ -1,8 +1,8 @@
+using DevExpress.DashboardWeb;
+using Microsoft.Data.SqlClient;
 using System.Data;
 using System.Text;
 using System.Xml.Linq;
-using DevExpress.DashboardWeb;
-using Microsoft.Data.SqlClient;

 namespace DbFirst.API.Dashboards;

@@ -100,7 +100,7 @@ public sealed class SqlDashboardStorage : IEditableDashboardStorage

        connection.Open();
        command.ExecuteNonQuery();
-        _notifier?.NotifyChanged();
+        _ = _notifier?.NotifyChangedAsync();
        return id;
    }

@@ -122,7 +122,7 @@ public sealed class SqlDashboardStorage : IEditableDashboardStorage
            throw new ArgumentException($"Dashboard '{dashboardId}' not found.");
        }

-        _notifier?.NotifyChanged();
+        _ = _notifier?.NotifyChangedAsync();
    }

    public void DeleteDashboard(string dashboardId)
@@ -133,6 +133,6 @@ public sealed class SqlDashboardStorage : IEditableDashboardStorage

        connection.Open();
        command.ExecuteNonQuery();
-        _notifier?.NotifyChanged();
+        _ = _notifier?.NotifyChangedAsync();
    }
 }
--- a/DbFirst.API/DbFirst.API.csproj
+++ b/DbFirst.API/DbFirst.API.csproj
@@ -7,8 +7,7 @@
  </PropertyGroup>

  <ItemGroup>
-    <PackageReference Include="AutoMapper" Version="12.0.1" />
-    <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="12.0.1" />
+    <PackageReference Include="AutoMapper" Version="16.1.1" />
    <PackageReference Include="DevExpress.AspNetCore.Dashboard" Version="25.2.3" />
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="8.0.22" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="8.0.22" />
@@ -17,7 +16,6 @@
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.6.2" />
-    <PackageReference Include="MediatR.Extensions.Microsoft.DependencyInjection" Version="11.1.0" />
  </ItemGroup>

  <ItemGroup>
--- a/DbFirst.API/Middleware/ExceptionHandlingMiddleware.cs
+++ b/DbFirst.API/Middleware/ExceptionHandlingMiddleware.cs
@@ -1,5 +1,4 @@
-using System.Net;
-using System.Text.Json;
+using Microsoft.AspNetCore.Mvc;

 namespace DbFirst.API.Middleware;

@@ -20,33 +19,35 @@ public class ExceptionHandlingMiddleware
        {
            await _next(context);
        }
+        catch (InvalidOperationException ex)
+        {
+            _logger.LogWarning(ex, "Domain validation error");
+            await WriteProblemAsync(context, StatusCodes.Status400BadRequest, "Eingabe ungültig", ex.Message);
+        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Unhandled exception");
-            await WriteProblemDetailsAsync(context, ex);
+            await WriteProblemAsync(context, StatusCodes.Status500InternalServerError, "Serverfehler", ex.Message);
        }
    }

-    private static async Task WriteProblemDetailsAsync(HttpContext context, Exception ex)
+    private static async Task WriteProblemAsync(HttpContext context, int status, string title, string detail)
    {
-        if (context.Response.HasStarted)
-        {
-            throw ex;
-        }
+        if (context.Response.HasStarted) return;

        context.Response.Clear();
-        context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
-        context.Response.ContentType = "application/json";
+        context.Response.StatusCode = status;
+        context.Response.ContentType = "application/problem+json";

-        var problem = new
+        var problem = new ProblemDetails
        {
-            type = "https://tools.ietf.org/html/rfc9110#section-15.6.1",
-            title = "Serverfehler",
-            status = context.Response.StatusCode,
-            detail = ex.Message,
-            traceId = context.TraceIdentifier
+            Type = $"https://tools.ietf.org/html/rfc9110#section-{(status == 400 ? "15.5.1" : "15.6.1")}",
+            Title = title,
+            Status = status,
+            Detail = detail,
+            Extensions = { ["traceId"] = context.TraceIdentifier }
        };

-        await context.Response.WriteAsync(JsonSerializer.Serialize(problem));
+        await context.Response.WriteAsJsonAsync(problem);
    }
 }
--- a/DbFirst.API/Program.cs
+++ b/DbFirst.API/Program.cs
@@ -1,18 +1,11 @@
-using DbFirst.API.Middleware;
 using DbFirst.API.Dashboards;
 using DbFirst.API.Hubs;
+using DbFirst.API.Middleware;
 using DbFirst.Application;
-using DbFirst.Application.Repositories;
-using DbFirst.Domain;
-using DbFirst.Domain.Entities;
 using DbFirst.Infrastructure;
-using DbFirst.Infrastructure.Repositories;
 using DevExpress.AspNetCore;
 using DevExpress.DashboardAspNetCore;
-using DevExpress.DashboardCommon;
 using DevExpress.DashboardWeb;
-using DevExpress.DataAccess.Json;
-using System.Xml.Linq;

 var builder = WebApplication.CreateBuilder(args);

@@ -20,6 +13,7 @@ var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddControllers();
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
+builder.Services.AddProblemDetails();

 // TODO: allow listed origins configured in appsettings.json
 // In any case, dont let them to free to use without cors. if there is no origin specified, block all.
@@ -36,7 +30,7 @@ builder.Services.AddCors(options =>
        }
        else
        {
-            var origins = builder.Configuration.GetSection("Cors:AllowedOrigins").Get<string[]>() ?? Array.Empty<string>();
+            var origins = builder.Configuration.GetSection("Cors:AllowedOrigins").Get<string[]>() ?? [];
            if (origins.Length > 0)
            {
                policy.WithOrigins(origins)
@@ -51,98 +45,11 @@ builder.Services.AddCors(options =>
 builder.Services.AddInfrastructure(builder.Configuration);
 builder.Services.AddApplication();

-builder.Services.AddScoped<ICatalogRepository, CatalogRepository>();
-builder.Services.AddScoped<IMassDataRepository, MassDataRepository>();
-builder.Services.AddScoped<ILayoutRepository, LayoutRepository>();
-
 builder.Services.AddDevExpressControls();
 builder.Services.AddSignalR();
 builder.Services.AddSingleton<IDashboardChangeNotifier, DashboardChangeNotifier>();
-builder.Services.AddScoped<DashboardConfigurator>((IServiceProvider serviceProvider) => {
-    var dashboardsPath = Path.Combine(builder.Environment.ContentRootPath, "Data", "Dashboards");
-    Directory.CreateDirectory(dashboardsPath);
-
-    var defaultDashboardPath = Path.Combine(dashboardsPath, "DefaultDashboard.xml");
-    if (!File.Exists(defaultDashboardPath))
-    {
-        var defaultDashboard = new Dashboard();
-        defaultDashboard.Title.Text = "Default Dashboard";
-        defaultDashboard.SaveToXml(defaultDashboardPath);
-    }
-
-    var dashboardBaseUrl = builder.Configuration["Dashboard:BaseUrl"]
-        ?? builder.Configuration["ApiBaseUrl"]
-        ?? builder.Configuration["ASPNETCORE_URLS"]?.Split(';', StringSplitOptions.RemoveEmptyEntries).FirstOrDefault()
-        ?? "https://localhost:7204";
-
-    dashboardBaseUrl = dashboardBaseUrl.TrimEnd('/');
-
-    var catalogsGridDashboardPath = Path.Combine(dashboardsPath, "CatalogsGrid.xml");
-    if (!File.Exists(catalogsGridDashboardPath))
-    {
-        var dashboard = new Dashboard();
-        dashboard.Title.Text = "Catalogs (Dashboard Grid)";
-
-        var catalogDataSource = new DashboardJsonDataSource("Catalogs (API)")
-        {
-            ComponentName = "catalogsDataSource",
-            JsonSource = new UriJsonSource(new Uri($"{dashboardBaseUrl}/api/catalogs"))
-        };
-
-        dashboard.DataSources.Add(catalogDataSource);
-
-        var grid = new GridDashboardItem
-        {
-            DataSource = catalogDataSource,
-            Name = "Catalogs"
-        };
-
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.Guid))) { Name = "Id" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.CatTitle))) { Name = "Titel" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.CatString))) { Name = "String" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.AddedWho))) { Name = "Angelegt von" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.AddedWhen))) { Name = "Angelegt am" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.ChangedWho))) { Name = "Geändert von" });
-        grid.Columns.Add(new GridDimensionColumn(new Dimension(nameof(VwmyCatalog.ChangedWhen))) { Name = "Geändert am" });
-
-        dashboard.Items.Add(grid);
-
-        var layoutGroup = new DashboardLayoutGroup { Orientation = DashboardLayoutGroupOrientation.Vertical };
-        layoutGroup.ChildNodes.Add(new DashboardLayoutItem(grid));
-        dashboard.LayoutRoot = layoutGroup;
-
-        dashboard.SaveToXml(catalogsGridDashboardPath);
-    }
-
-    DashboardConfigurator configurator = new DashboardConfigurator();
-
-    var connectionString = builder.Configuration.GetConnectionString("DefaultConnection") ?? string.Empty;
-    var notifier = serviceProvider.GetRequiredService<IDashboardChangeNotifier>();
-    var dashboardStorage = new SqlDashboardStorage(connectionString, "TBDD_SMF_CONFIG", notifier: notifier);
-    configurator.SetDashboardStorage(dashboardStorage);
-
-    DataSourceInMemoryStorage dataSourceStorage = new DataSourceInMemoryStorage();
-    DashboardJsonDataSource jsonDataSourceUrl = new DashboardJsonDataSource("JSON Data Source (URL)");
-    jsonDataSourceUrl.JsonSource = new UriJsonSource(
-            new Uri("https://raw.githubusercontent.com/DevExpress-Examples/DataSources/master/JSON/customers.json"));
-    jsonDataSourceUrl.RootElement = "Customers";
-    dataSourceStorage.RegisterDataSource("jsonDataSourceUrl", jsonDataSourceUrl.SaveToXml());
-
-    var catalogsJsonDataSource = new DashboardJsonDataSource("Catalogs (API)")
-    {
-        ComponentName = "catalogsDataSource",
-        JsonSource = new UriJsonSource(new Uri($"{dashboardBaseUrl}/api/catalogs"))
-    };
-    dataSourceStorage.RegisterDataSource(catalogsJsonDataSource.ComponentName, catalogsJsonDataSource.SaveToXml());
-    dataSourceStorage.RegisterDataSource(catalogsJsonDataSource.Name, catalogsJsonDataSource.SaveToXml());
-
-    configurator.SetDataSourceStorage(dataSourceStorage);
-
-    EnsureDashboardInStorage(dashboardStorage, "DefaultDashboard", defaultDashboardPath);
-    EnsureDashboardInStorage(dashboardStorage, "CatalogsGrid", catalogsGridDashboardPath);
-
-    return configurator;
-});
+builder.Services.AddScoped<DashboardConfigurator>(sp =>
+    DashboardConfiguratorFactory.Create(sp, builder.Configuration, builder.Environment));

 var app = builder.Build();

@@ -164,16 +71,4 @@ app.MapDashboardRoute("api/dashboard", "DefaultDashboard");
 app.MapHub<DashboardsHub>("/hubs/dashboards");
 app.MapControllers();

-app.Run();
-
-static void EnsureDashboardInStorage(IEditableDashboardStorage storage, string id, string filePath)
-{
-    var exists = storage.GetAvailableDashboardsInfo().Any(info => string.Equals(info.ID, id, StringComparison.OrdinalIgnoreCase));
-    if (exists || !File.Exists(filePath))
-    {
-        return;
-    }
-
-    var doc = XDocument.Load(filePath);
-    storage.AddDashboard(doc, id);
-}
+app.Run();
--- a/DbFirst.Application/Catalogs/CatalogProfile.cs
+++ b/DbFirst.Application/Catalogs/CatalogProfile.cs
@@ -1,4 +1,5 @@
 using AutoMapper;
+using DbFirst.Contracts.Catalogs;
 using DbFirst.Domain.Entities;

 namespace DbFirst.Application.Catalogs;
--- a/DbFirst.Application/Catalogs/CatalogReadDto.cs
+++ b/DbFirst.Application/Catalogs/CatalogReadDto.cs
@@ -1,12 +0,0 @@
-namespace DbFirst.Application.Catalogs;
-
-public class CatalogReadDto
-{
-    public int Guid { get; set; }
-    public string CatTitle { get; set; } = null!;
-    public string CatString { get; set; } = null!;
-    public string AddedWho { get; set; } = null!;
-    public DateTime AddedWhen { get; set; }
-    public string? ChangedWho { get; set; }
-    public DateTime? ChangedWhen { get; set; }
-}
--- a/DbFirst.Application/Catalogs/CatalogWriteDto.cs
+++ b/DbFirst.Application/Catalogs/CatalogWriteDto.cs
@@ -1,10 +0,0 @@
-using DbFirst.Domain;
-
-namespace DbFirst.Application.Catalogs;
-
-public class CatalogWriteDto
-{
-    public string CatTitle { get; set; } = null!;
-    public string CatString { get; set; } = null!;
-    public CatalogUpdateProcedure UpdateProcedure { get; set; } = CatalogUpdateProcedure.Update;
-}
--- a/DbFirst.Application/Catalogs/Commands/CreateCatalogCommand.cs
+++ b/DbFirst.Application/Catalogs/Commands/CreateCatalogCommand.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Commands;
--- a/DbFirst.Application/Catalogs/Commands/CreateCatalogHandler.cs
+++ b/DbFirst.Application/Catalogs/Commands/CreateCatalogHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.Catalogs;
 using DbFirst.Domain.Entities;
 using MediatR;

--- a/DbFirst.Application/Catalogs/Commands/UpdateCatalogCommand.cs
+++ b/DbFirst.Application/Catalogs/Commands/UpdateCatalogCommand.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Commands;
--- a/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs
+++ b/DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs
@@ -1,7 +1,8 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
-using DbFirst.Domain.Entities;
+using DbFirst.Contracts.Catalogs;
 using DbFirst.Domain;
+using DbFirst.Domain.Entities;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Commands;
@@ -25,18 +26,20 @@ public class UpdateCatalogHandler : IRequestHandler<UpdateCatalogCommand, Catalo
            return null;
        }

+        if (request.Dto.UpdateProcedure == CatalogUpdateProcedure.Update &&
+            !string.Equals(existing.CatTitle, request.Dto.CatTitle, StringComparison.OrdinalIgnoreCase))
+        {
+            throw new InvalidOperationException("Titel kann nicht geändert werden.");
+        }
+
        var entity = _mapper.Map<VwmyCatalog>(request.Dto);
        entity.Guid = request.Id;
-        entity.CatTitle = request.Dto.UpdateProcedure == CatalogUpdateProcedure.Update
-            ? existing.CatTitle
-            : request.Dto.CatTitle;
        entity.AddedWho = existing.AddedWho;
        entity.AddedWhen = existing.AddedWhen;
        entity.ChangedWho = "system";
        entity.ChangedWhen = DateTime.UtcNow;

-        var procedure = request.Dto.UpdateProcedure;
-        var updated = await _repository.UpdateAsync(request.Id, entity, procedure, cancellationToken);
+        var updated = await _repository.UpdateAsync(request.Id, entity, request.Dto.UpdateProcedure, cancellationToken);
        return updated == null ? null : _mapper.Map<CatalogReadDto>(updated);
    }
 }
--- a/DbFirst.Application/Catalogs/Queries/GetAllCatalogsHandler.cs
+++ b/DbFirst.Application/Catalogs/Queries/GetAllCatalogsHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Queries;
--- a/DbFirst.Application/Catalogs/Queries/GetAllCatalogsQuery.cs
+++ b/DbFirst.Application/Catalogs/Queries/GetAllCatalogsQuery.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Queries;
--- a/DbFirst.Application/Catalogs/Queries/GetCatalogByIdHandler.cs
+++ b/DbFirst.Application/Catalogs/Queries/GetCatalogByIdHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Queries;
--- a/DbFirst.Application/Catalogs/Queries/GetCatalogByIdQuery.cs
+++ b/DbFirst.Application/Catalogs/Queries/GetCatalogByIdQuery.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.Catalogs;
 using MediatR;

 namespace DbFirst.Application.Catalogs.Queries;
--- a/DbFirst.Application/DbFirst.Application.csproj
+++ b/DbFirst.Application/DbFirst.Application.csproj
@@ -7,14 +7,18 @@
  </PropertyGroup>

  <ItemGroup>
-    <PackageReference Include="AutoMapper" Version="12.0.1" />
-    <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="12.0.1" />
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="8.0.2" />
-    <PackageReference Include="MediatR.Extensions.Microsoft.DependencyInjection" Version="11.1.0" />
+    <PackageReference Include="AutoMapper" Version="16.1.1" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="10.0.0" />
+	<PackageReference Include="MediatR" Version="14.1.0" />
  </ItemGroup>

  <ItemGroup>
+    <ProjectReference Include="..\DbFirst.Contracts\DbFirst.Contracts.csproj" />
    <ProjectReference Include="..\DbFirst.Domain\DbFirst.Domain.csproj" />
  </ItemGroup>

+  <ItemGroup>
+    <Folder Include="Layouts\" />
+  </ItemGroup>
+
 </Project>
--- a/DbFirst.Application/DependencyInjection.cs
+++ b/DbFirst.Application/DependencyInjection.cs
@@ -1,5 +1,4 @@
 using Microsoft.Extensions.DependencyInjection;
-using MediatR;

 namespace DbFirst.Application;

@@ -7,8 +6,9 @@ public static class DependencyInjection
 {
    public static IServiceCollection AddApplication(this IServiceCollection services)
    {
-        services.AddAutoMapper(typeof(DependencyInjection).Assembly);
-        services.AddMediatR(typeof(DependencyInjection).Assembly);
+        services.AddAutoMapper(cfg => cfg.AddMaps(typeof(DependencyInjection).Assembly));
+        services.AddMediatR(cfg =>
+    cfg.RegisterServicesFromAssembly(typeof(DependencyInjection).Assembly));
        return services;
    }
 }
--- a/DbFirst.Application/MassData/Commands/UpsertMassDataByCustomerNameCommand.cs
+++ b/DbFirst.Application/MassData/Commands/UpsertMassDataByCustomerNameCommand.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Commands;
--- a/DbFirst.Application/MassData/Commands/UpsertMassDataByCustomerNameHandler.cs
+++ b/DbFirst.Application/MassData/Commands/UpsertMassDataByCustomerNameHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Commands;
--- a/DbFirst.Application/MassData/MassDataProfile.cs
+++ b/DbFirst.Application/MassData/MassDataProfile.cs
@@ -1,4 +1,5 @@
 using AutoMapper;
+using DbFirst.Contracts.MassData;
 using DbFirst.Domain.Entities;

 namespace DbFirst.Application.MassData;
--- a/DbFirst.Application/MassData/MassDataReadDto.cs
+++ b/DbFirst.Application/MassData/MassDataReadDto.cs
@@ -1,12 +0,0 @@
-namespace DbFirst.Application.MassData;
-
-public class MassDataReadDto
-{
-    public int Id { get; set; }
-    public string CustomerName { get; set; } = string.Empty;
-    public decimal Amount { get; set; }
-    public string Category { get; set; } = string.Empty;
-    public bool StatusFlag { get; set; }
-    public DateTime AddedWhen { get; set; }
-    public DateTime? ChangedWhen { get; set; }
-}
--- a/DbFirst.Application/MassData/MassDataWriteDto.cs
+++ b/DbFirst.Application/MassData/MassDataWriteDto.cs
@@ -1,9 +0,0 @@
-namespace DbFirst.Application.MassData;
-
-public class MassDataWriteDto
-{
-    public string CustomerName { get; set; } = string.Empty;
-    public decimal Amount { get; set; }
-    public string Category { get; set; } = string.Empty;
-    public bool StatusFlag { get; set; }
-}
--- a/DbFirst.Application/MassData/Queries/GetAllMassDataHandler.cs
+++ b/DbFirst.Application/MassData/Queries/GetAllMassDataHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Queries;
--- a/DbFirst.Application/MassData/Queries/GetAllMassDataQuery.cs
+++ b/DbFirst.Application/MassData/Queries/GetAllMassDataQuery.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Queries;
--- a/DbFirst.Application/MassData/Queries/GetMassDataByCustomerNameHandler.cs
+++ b/DbFirst.Application/MassData/Queries/GetMassDataByCustomerNameHandler.cs
@@ -1,5 +1,6 @@
 using AutoMapper;
 using DbFirst.Application.Repositories;
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Queries;
--- a/DbFirst.Application/MassData/Queries/GetMassDataByCustomerNameQuery.cs
+++ b/DbFirst.Application/MassData/Queries/GetMassDataByCustomerNameQuery.cs
@@ -1,3 +1,4 @@
+using DbFirst.Contracts.MassData;
 using MediatR;

 namespace DbFirst.Application.MassData.Queries;
--- a/DbFirst.BlazorWasm/Ablauf.cs
+++ b/DbFirst.BlazorWasm/Ablauf.cs
@@ -1,60 +0,0 @@
-/*
-Ablauf und die Rolle jeder Datei in der Blazor WebAssembly-Anwendung:
-
-1.index.html
-•	Reihenfolge: Wird als erstes geladen, wenn die Anwendung im Browser geöffnet wird.
-•	Purpose:
-•	Lädt die Blazor WebAssembly-Umgebung (blazor.webassembly.js).
-•	Definiert den Platzhalter <div id="app">, in dem die Blazor-Komponenten gerendert werden.
-•	Bindet Stylesheets und Skripte ein, die für das Styling und die Funktionalität der Anwendung benötigt werden.
-
-2. Program.cs
-•	Reihenfolge: Wird nach index.html ausgeführt, sobald die Blazor-Umgebung initialisiert ist.
-•	Purpose:
-•	Initialisiert die Blazor WebAssembly-Anwendung.
-•	Registriert Root-Komponenten (App) und Abhängigkeiten (z. B. HttpClient, CatalogApiClient).
-•	Konfiguriert die Basis-URL für API-Aufrufe.
-
-3. App.razor
-•	Reihenfolge: Wird als nächstes geladen, nachdem die Anwendung initialisiert wurde.
-•	Purpose:
-•	Definiert die Routing-Logik der Anwendung.
-•	Entscheidet, welche Komponente basierend auf der URL gerendert wird.
-•	Stellt sicher, dass ein Standardlayout (MainLayout) verwendet wird.
-
-4.MainLayout.razor
-•	Reihenfolge: Wird geladen, wenn eine Seite gerendert wird, da es das Standardlayout ist.
-•	Purpose:
-•	Definiert das Hauptlayout der Anwendung.
-•	Enthält die Navigationsleiste (NavMenu) und den Platzhalter für den Seiteninhalt (@Body).
-
-5. NavMenu.razor
-•	Reihenfolge: Wird als Teil des Layouts (MainLayout) geladen.
-•	Purpose:
-•	Stellt die Navigationsleiste bereit.
-•	Enthält Links zu verschiedenen Seiten der Anwendung (z. B. Home, Catalogs).
-•	Ermöglicht das Ein- und Ausklappen des Menüs.
-
-6. Catalogs.razor
-•	Reihenfolge: Wird geladen, wenn der Benutzer die URL /catalogs aufruft.
-•	Purpose:
-•	Stellt die Benutzeroberfläche für die Verwaltung von Katalogen bereit.
-•	Nutzt CatalogApiClient, um Daten von der API zu laden, zu erstellen, zu aktualisieren oder zu löschen.
-•	Verwendet DevExpress-Komponenten für ein modernes UI.
-
-7. CatalogApiClient.cs
-•	Reihenfolge: Wird verwendet, wenn Catalogs.razor API-Aufrufe ausführt.
-•	Purpose:
-•	Kapselt die Kommunikation mit der API.
-•	Bietet Methoden für CRUD-Operationen (Create, Read, Update, Delete) auf Katalog-Daten.
-•	Behandelt Fehler und gibt benutzerfreundliche Fehlermeldungen zurück.
-
-Zusammenfassung des Ablaufs:
-1.index.html: Lädt die Blazor-Umgebung und startet die Anwendung.
-2.	Program.cs: Initialisiert die Anwendung und registriert Abhängigkeiten.
-3.	App.razor: Definiert die Routing-Logik und lädt das Standardlayout.
-4.	MainLayout.razor: Stellt das Hauptlayout bereit.
-5.	NavMenu.razor: Lädt die Navigationsleiste.
-6.	Seiten wie Catalogs.razor: Werden basierend auf der URL gerendert.
-7.	CatalogApiClient.cs: Führt API-Aufrufe aus, wenn die Seite Daten benötigt.
-*/
--- a/DbFirst.BlazorWasm/App.razor
+++ b/DbFirst.BlazorWasm/App.razor
@@ -1,20 +0,0 @@
-@* 
-•	Ist der logische Einstiegspunkt der Blazor-Anwendung.
-•	Sie definiert die Routing-Logik und das Standardlayout der Anwendung.
-•	Der Router-Komponent in App.razor entscheidet, welche Blazor-Komponente basierend auf der URL geladen wird.
-    kurz: Steuert die Navigation und das Rendering der Blazor-Komponenten.
-    *@
-@DxResourceManager.RegisterTheme(Themes.Fluent)
-@DxResourceManager.RegisterScripts()
-<Router AppAssembly="@typeof(App).Assembly">
-    <Found Context="routeData">
-        <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
-        <FocusOnNavigate RouteData="@routeData" Selector="h1" />
-    </Found>
-    <NotFound>
-        <PageTitle>Not found</PageTitle>
-        <LayoutView Layout="@typeof(MainLayout)">
-            <p role="alert">Sorry, there's nothing at this address.</p>
-        </LayoutView>
-    </NotFound>
-</Router>
--- a/DbFirst.BlazorWasm/Components/CatalogsGrid.razor
+++ b/DbFirst.BlazorWasm/Components/CatalogsGrid.razor
@@ -1,897 +0,0 @@
-@using System.Text.Json
-@using Microsoft.AspNetCore.Components
-@using Microsoft.AspNetCore.Components.Rendering
-@using Microsoft.AspNetCore.Components.Forms
-@using DevExpress.Blazor
-@using DevExpress.Data.Filtering
-@inject CatalogApiClient Api
-@inject LayoutApiClient LayoutApi
-@inject IJSRuntime JsRuntime
-
-<style>
-    .action-panel { margin-bottom: 16px; }
-    .grid-section { margin-top: 12px; }
-    .catalog-grid .dxbl-grid-sort-asc,
-    .catalog-grid .dxbl-grid-sort-desc {
-        display: none;
-    }
-    .catalog-grid th.dxbl-grid-header-sortable {
-        position: relative;
-        padding-right: 1.5rem;
-    }
-    .catalog-grid th.dxbl-grid-header-sortable::before,
-    .catalog-grid th.dxbl-grid-header-sortable::after {
-        content: "";
-        position: absolute;
-        right: 0.45rem;
-        width: 0.7rem;
-        height: 0.7rem;
-        background-repeat: no-repeat;
-        background-size: 0.7rem 0.7rem;
-        opacity: 0.35;
-        pointer-events: none;
-    }
-    .catalog-grid th.dxbl-grid-header-sortable::before {
-        top: 38%;
-        background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M4.957 10.999a1 1 0 0 1-.821-1.571l2.633-3.785a1.5 1.5 0 0 1 2.462 0l2.633 3.785a1 1 0 0 1-.821 1.57H4.957Z' fill='%23888888'/%3E%3C/svg%3E");
-    }
-    .catalog-grid th.dxbl-grid-header-sortable::after {
-        top: 58%;
-        background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M4.957 5a1 1 0 0 0-.821 1.571l2.633 3.784a1.5 1.5 0 0 0 2.462 0l2.633-3.784A1 1 0 0 0 11.043 5H4.957Z' fill='%23888888'/%3E%3C/svg%3E");
-    }
-    .catalog-grid th.dxbl-grid-header-sortable[aria-sort="ascending"]::after {
-        opacity: 0;
-    }
-    .catalog-grid th.dxbl-grid-header-sortable[aria-sort="descending"]::before {
-        opacity: 0;
-    }
-    .catalog-grid .filter-search-input input {
-        padding-right: 1.75rem;
-        background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M9.309 10.016a4.5 4.5 0 1 1 .707-.707l3.838 3.837a.5.5 0 0 1-.708.708L9.31 10.016ZM10 6.5a3.5 3.5 0 1 0-7 0 3.5 3.5 0 0 0 7 0Z' fill='%23666666'/%3E%3C/svg%3E");
-        background-repeat: no-repeat;
-        background-position: right 0.5rem center;
-        background-size: 0.9rem;
-    }
-    .catalog-edit-popup {
-        min-width: 720px;
-    }
-    .band-editor {
-        display: grid;
-        gap: 12px;
-        margin-bottom: 16px;
-    }
-    .band-controls {
-        display: flex;
-        flex-wrap: wrap;
-        gap: 8px;
-        align-items: center;
-    }
-    .band-row {
-        display: flex;
-        gap: 8px;
-        align-items: center;
-    }
-    .band-columns {
-        max-width: 720px;
-    }
-    .filter-row-cell {
-        display: flex;
-        align-items: center;
-        gap: 4px;
-        flex-wrap: wrap;
-    }
-    .filter-operator {
-        width: 52px;
-        min-width: 52px;
-        flex: 0 0 52px;
-    }
-    .filter-value {
-        min-width: 140px;
-        flex: 1 1 140px;
-    }
-</style>
-
-@if (!string.IsNullOrWhiteSpace(errorMessage))
-{
-    <div class="alert alert-danger" role="alert">@errorMessage</div>
-}
-else if (!string.IsNullOrWhiteSpace(infoMessage))
-{
-    <div class="alert alert-success" role="alert">@infoMessage</div>
-}
-
-@if (isLoading)
-{
-    <p><em>Lade Daten...</em></p>
-}
-else if (items.Count == 0)
-{
-    <p>Keine Einträge vorhanden.</p>
-}
-else
-{
-    <div class="band-editor">
-        <div class="band-controls">
-            <DxButton Text="Band hinzufügen" Click="AddBand" />
-            <DxButton Text="Layout speichern" Click="SaveLayoutAsync" Enabled="@CanSaveBandLayout" />
-            <DxButton Text="Band-Layout zurücksetzen" Click="ResetBandLayoutAsync" />
-        </div>
-        @foreach (var band in bandLayout.Bands)
-        {
-            <div class="band-row">
-                <DxTextBox Text="@band.Caption" TextChanged="@(value => UpdateBandCaption(band, value))" />
-                <DxButton Text="Entfernen" Click="@(() => RemoveBand(band))" />
-            </div>
-        }
-        <DxFormLayout CssClass="band-columns" ColCount="2">
-            @foreach (var column in columnDefinitions)
-            {
-                <DxFormLayoutItem Caption="@column.Caption">
-                    <DxComboBox Data="@bandOptions"
-                                TData="BandOption"
-                                TValue="string"
-                                TextFieldName="Caption"
-                                ValueFieldName="Id"
-                                Value="@GetColumnBand(column.FieldName)"
-                                ValueChanged="@(value => UpdateColumnBand(column.FieldName, value))"
-                                Width="100%" />
-                </DxFormLayoutItem>
-            }
-        </DxFormLayout>
-    </div>
-
-    <div class="grid-section">
-        <DxGrid Data="@items"
-                TItem="CatalogReadDto"
-                KeyFieldName="@nameof(CatalogReadDto.Guid)"
-                ShowGroupPanel="true"
-                ShowGroupedColumns="true"
-                AllowGroup="true"
-                ShowFilterRow="true"
-                AllowColumnResize="true"
-                ColumnResizeMode="GridColumnResizeMode.ColumnsContainer"
-                AllowColumnReorder="true"
-                PageSize="10"
-                CssClass="mb-4 catalog-grid"
-                EditMode="GridEditMode.PopupEditForm"
-                PopupEditFormCssClass="catalog-edit-popup"
-                PopupEditFormHeaderText="@popupHeaderText"
-                CustomizeEditModel="OnCustomizeEditModel"
-                EditModelSaving="OnEditModelSaving"
-                DataItemDeleting="OnDataItemDeleting"
-                @ref="gridRef">
-            <Columns>
-                @RenderColumns()
-            </Columns>
-            <EditFormTemplate Context="editFormContext">
-                @{ SetEditContext(editFormContext.EditContext); var editModel = (CatalogEditModel)editFormContext.EditModel; SetPopupHeaderText(editModel.IsNew); }
-                <DxFormLayout ColCount="2">
-                    <DxFormLayoutItem Caption="Titel">
-                        <DxTextBox @bind-Text="editModel.CatTitle" Width="100%" />
-                    </DxFormLayoutItem>
-                    <DxFormLayoutItem Caption="Kennung">
-                        <DxTextBox @bind-Text="editModel.CatString" Width="100%" />
-                    </DxFormLayoutItem>
-                    @if (!editModel.IsNew)
-                    {
-                        <DxFormLayoutItem Caption="Update-Prozedur">
-                            <DxComboBox Data="@procedureOptions"
-                                        TData="ProcedureOption"
-                                        TValue="int"
-                                        TextFieldName="Text"
-                                        ValueFieldName="Value"
-                                        @bind-Value="editModel.UpdateProcedure"
-                                        Width="100%" />
-                        </DxFormLayoutItem>
-                    }
-                    <DxFormLayoutItem ColSpanMd="12">
-                        <ValidationSummary />
-                    </DxFormLayoutItem>
-                </DxFormLayout>
-            </EditFormTemplate>
-        </DxGrid>
-    </div>
-}
-
-@code {
-    private List<CatalogReadDto> items = new();
-    private bool isLoading;
-    private string? errorMessage;
-    private string? infoMessage;
-    private EditContext? editContext;
-    private ValidationMessageStore? validationMessageStore;
-    private IGrid? gridRef;
-    private string popupHeaderText = "Edit";
-    private DateTime? addedWhenFilterValue;
-    private string addedWhenFilterOperator = "=";
-    private DateTime? changedWhenFilterValue;
-    private string changedWhenFilterOperator = "=";
-    private const string LayoutType = "GRID_BANDS";
-    private const string LayoutKey = "CatalogsGrid";
-    private const string LayoutUserStorageKey = "layoutUser";
-    private string? layoutUser;
-    private BandLayout bandLayout = new();
-    private Dictionary<string, string> columnBandAssignments = new();
-    private List<BandOption> bandOptions = new();
-    private Dictionary<string, ColumnDefinition> columnLookup = new();
-    private readonly JsonSerializerOptions jsonOptions = new(JsonSerializerDefaults.Web);
-    private List<ColumnDefinition> columnDefinitions = new()
-    {
-        new() { FieldName = nameof(CatalogReadDto.Guid), Caption = "Id", Width = "140px", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.CatTitle), Caption = "Titel", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.CatString), Caption = "String", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.AddedWho), Caption = "Angelegt von", ReadOnly = true, FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.AddedWhen), Caption = "Angelegt am", ReadOnly = true, FilterType = ColumnFilterType.Date },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWho), Caption = "Geändert von", ReadOnly = true, FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWhen), Caption = "Geändert am", ReadOnly = true, FilterType = ColumnFilterType.Date }
-    };
-
-    private readonly List<ProcedureOption> procedureOptions = new()
-    {
-        new() { Value = 0, Text = "PRTBMY_CATALOG_UPDATE" },
-        new() { Value = 1, Text = "PRTBMY_CATALOG_SAVE" }
-    };
-
-    private readonly List<FilterOperatorOption> filterOperators = new()
-    {
-        new() { Value = "=", Text = "=" },
-        new() { Value = "<", Text = "<" },
-        new() { Value = ">", Text = ">" },
-        new() { Value = "<=", Text = "<=" },
-        new() { Value = ">=", Text = ">=" }
-    };
-
-    private bool CanSaveBandLayout => !string.IsNullOrWhiteSpace(layoutUser);
-    private bool gridLayoutApplied;
-
-    protected override async Task OnInitializedAsync()
-    {
-        columnLookup = columnDefinitions.ToDictionary(column => column.FieldName, StringComparer.OrdinalIgnoreCase);
-        await EnsureLayoutUserAsync();
-        await LoadBandLayoutAsync();
-        await LoadCatalogs();
-    }
-
-    protected override async Task OnAfterRenderAsync(bool firstRender)
-    {
-        if (!gridLayoutApplied && gridRef != null && bandLayout.GridLayout != null)
-        {
-            gridRef.LoadLayout(bandLayout.GridLayout);
-            gridLayoutApplied = true;
-            await InvokeAsync(StateHasChanged);
-        }
-    }
-
-    private void SetEditContext(EditContext context)
-    {
-        if (editContext == context)
-        {
-            return;
-        }
-
-        if (editContext != null)
-        {
-            editContext.OnFieldChanged -= OnEditFieldChanged;
-        }
-
-        editContext = context;
-        validationMessageStore = new ValidationMessageStore(editContext);
-        editContext.OnFieldChanged += OnEditFieldChanged;
-    }
-
-    private void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
-    {
-        if (validationMessageStore == null || editContext == null)
-        {
-            return;
-        }
-
-        if (e.FieldIdentifier.FieldName == nameof(CatalogEditModel.UpdateProcedure))
-        {
-            validationMessageStore.Clear();
-            editContext.NotifyValidationStateChanged();
-            return;
-        }
-
-        if (e.FieldIdentifier.FieldName == nameof(CatalogEditModel.CatTitle))
-        {
-            var field = new FieldIdentifier(editContext.Model, nameof(CatalogEditModel.CatTitle));
-            validationMessageStore.Clear(field);
-            editContext.NotifyValidationStateChanged();
-        }
-    }
-
-    private void SetPopupHeaderText(bool isNew)
-    {
-        popupHeaderText = isNew ? "Neu" : "Edit";
-    }
-
-    private void OnCustomizeEditModel(GridCustomizeEditModelEventArgs e)
-    {
-        popupHeaderText = e.IsNew ? "Neu" : "Edit";
-        if (e.IsNew)
-        {
-            e.EditModel = new CatalogEditModel { IsNew = true };
-            return;
-        }
-
-        var item = (CatalogReadDto)e.DataItem;
-        e.EditModel = new CatalogEditModel
-        {
-            Guid = item.Guid,
-            CatTitle = item.CatTitle,
-            CatString = item.CatString,
-            UpdateProcedure = 0,
-            OriginalCatTitle = item.CatTitle,
-            IsNew = false
-        };
-    }
-
-    private async Task LoadCatalogs()
-    {
-        isLoading = true;
-        errorMessage = null;
-        try
-        {
-            items = await Api.GetAllAsync();
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Kataloge konnten nicht geladen werden: {ex.Message}";
-        }
-        finally
-        {
-            isLoading = false;
-            StateHasChanged();
-        }
-    }
-
-    private async Task OnEditModelSaving(GridEditModelSavingEventArgs e)
-    {
-        errorMessage = null;
-        infoMessage = null;
-
-        validationMessageStore?.Clear();
-        editContext?.NotifyValidationStateChanged();
-
-        var editModel = (CatalogEditModel)e.EditModel;
-        if (!ValidateEditModel(editModel, e.IsNew))
-        {
-            e.Cancel = true;
-            return;
-        }
-
-        var dto = new CatalogWriteDto
-        {
-            CatTitle = editModel.CatTitle,
-            CatString = editModel.CatString,
-            UpdateProcedure = editModel.UpdateProcedure
-        };
-
-        try
-        {
-            if (e.IsNew)
-            {
-                var created = await Api.CreateAsync(dto);
-                if (!created.Success || created.Value == null)
-                {
-                    if (!string.IsNullOrWhiteSpace(created.Error))
-                    {
-                        AddValidationError(editModel, nameof(CatalogEditModel.CatTitle), created.Error);
-                    }
-                    else
-                    {
-                        errorMessage = "Anlegen fehlgeschlagen.";
-                    }
-
-                    e.Cancel = true;
-                    return;
-                }
-
-                infoMessage = "Katalog angelegt.";
-            }
-            else
-            {
-                var updated = await Api.UpdateAsync(editModel.Guid, dto);
-                if (!updated.Success)
-                {
-                    errorMessage = updated.Error ?? "Aktualisierung fehlgeschlagen.";
-                    e.Cancel = true;
-                    return;
-                }
-
-                infoMessage = "Katalog aktualisiert.";
-            }
-
-            await LoadCatalogs();
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Fehler beim Speichern: {ex.Message}";
-            e.Cancel = true;
-        }
-    }
-
-    private void AddValidationError(CatalogEditModel editModel, string fieldName, string message)
-    {
-        if (editContext == null || validationMessageStore == null)
-        {
-            return;
-        }
-
-        var field = new FieldIdentifier(editModel, fieldName);
-        validationMessageStore.Add(field, message);
-        editContext.NotifyValidationStateChanged();
-    }
-
-    private bool ValidateEditModel(CatalogEditModel editModel, bool isNew)
-    {
-        if (isNew)
-        {
-            return true;
-        }
-
-        if (editModel.UpdateProcedure == 0 &&
-            !string.Equals(editModel.CatTitle, editModel.OriginalCatTitle, StringComparison.OrdinalIgnoreCase))
-        {
-            AddValidationError(editModel, nameof(CatalogEditModel.CatTitle), "Titel kann nicht geändert werden.");
-            return false;
-        }
-
-        return true;
-    }
-
-    private async Task OnDataItemDeleting(GridDataItemDeletingEventArgs e)
-    {
-        errorMessage = null;
-        infoMessage = null;
-
-        var item = (CatalogReadDto)e.DataItem;
-
-        try
-        {
-            var deleted = await Api.DeleteAsync(item.Guid);
-            if (!deleted.Success)
-            {
-                errorMessage = deleted.Error ?? "Löschen fehlgeschlagen.";
-                e.Cancel = true;
-                return;
-            }
-
-            infoMessage = "Katalog gelöscht.";
-            await LoadCatalogs();
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Fehler beim Löschen: {ex.Message}";
-            e.Cancel = true;
-        }
-    }
-
-    private async Task EnsureLayoutUserAsync()
-    {
-        layoutUser = await JsRuntime.InvokeAsync<string?>("localStorage.getItem", LayoutUserStorageKey);
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            layoutUser = Guid.NewGuid().ToString("N");
-            await JsRuntime.InvokeVoidAsync("localStorage.setItem", LayoutUserStorageKey, layoutUser);
-        }
-    }
-
-    private async Task LoadBandLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            bandLayout = new BandLayout();
-            UpdateBandOptions();
-            return;
-        }
-
-        var stored = await LayoutApi.GetAsync(LayoutType, LayoutKey, layoutUser);
-        if (stored != null && !string.IsNullOrWhiteSpace(stored.LayoutData))
-        {
-            var parsed = JsonSerializer.Deserialize<BandLayout>(stored.LayoutData, jsonOptions);
-            bandLayout = NormalizeBandLayout(parsed);
-        }
-        else
-        {
-            bandLayout = new BandLayout();
-        }
-
-        columnBandAssignments = BuildAssignmentsFromLayout(bandLayout);
-        ApplyColumnLayoutFromStorage();
-        UpdateBandOptions();
-    }
-
-    private async Task SaveLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            return;
-        }
-
-        try
-        {
-            CaptureColumnLayoutFromGrid();
-
-            var layoutData = JsonSerializer.Serialize(bandLayout, jsonOptions);
-            await LayoutApi.UpsertAsync(new LayoutDto
-            {
-                LayoutType = LayoutType,
-                LayoutKey = LayoutKey,
-                UserName = layoutUser,
-                LayoutData = layoutData
-            });
-            infoMessage = "Layout gespeichert.";
-            errorMessage = null;
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Layout konnte nicht gespeichert werden: {ex.Message}";
-        }
-    }
-
-    private void CaptureColumnLayoutFromGrid()
-    {
-        if (gridRef == null)
-        {
-            return;
-        }
-
-        var layout = gridRef.SaveLayout();
-        bandLayout.GridLayout = layout;
-
-        var orderedColumns = layout.Columns
-            .Where(column => !string.IsNullOrWhiteSpace(column.FieldName))
-            .OrderBy(column => column.VisibleIndex)
-            .ToList();
-
-        bandLayout.ColumnOrder = orderedColumns
-            .Select(column => column.FieldName)
-            .ToList();
-
-        bandLayout.ColumnWidths = orderedColumns
-            .Where(column => !string.IsNullOrWhiteSpace(column.Width))
-            .ToDictionary(column => column.FieldName, column => column.Width, StringComparer.OrdinalIgnoreCase);
-    }
-
-    private async Task ResetBandLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            return;
-        }
-
-        await LayoutApi.DeleteAsync(LayoutType, LayoutKey, layoutUser);
-        bandLayout = new BandLayout();
-        columnBandAssignments.Clear();
-        UpdateBandOptions();
-        infoMessage = "Band-Layout zurückgesetzt.";
-    }
-
-    private void ApplyColumnLayoutFromStorage()
-    {
-        foreach (var column in columnDefinitions)
-        {
-            if (bandLayout.ColumnWidths.TryGetValue(column.FieldName, out var width) && !string.IsNullOrWhiteSpace(width))
-            {
-                column.Width = width;
-            }
-        }
-
-        columnLookup = columnDefinitions.ToDictionary(column => column.FieldName, StringComparer.OrdinalIgnoreCase);
-    }
-
-    private void AddBand()
-    {
-        bandLayout.Bands.Add(new BandDefinition
-        {
-            Id = Guid.NewGuid().ToString("N"),
-            Caption = "Band"
-        });
-        UpdateBandOptions();
-    }
-
-    private void RemoveBand(BandDefinition band)
-    {
-        bandLayout.Bands.Remove(band);
-        var removedColumns = columnBandAssignments.Where(pair => pair.Value == band.Id)
-            .Select(pair => pair.Key)
-            .ToList();
-        foreach (var column in removedColumns)
-        {
-            columnBandAssignments.Remove(column);
-        }
-        UpdateBandOptions();
-        SyncBandsFromAssignments();
-    }
-
-    private void UpdateBandCaption(BandDefinition band, string value)
-    {
-        band.Caption = value;
-        UpdateBandOptions();
-    }
-
-    private void UpdateColumnBand(string fieldName, string? bandId)
-    {
-        if (string.IsNullOrWhiteSpace(bandId))
-        {
-            columnBandAssignments.Remove(fieldName);
-        }
-        else
-        {
-            columnBandAssignments[fieldName] = bandId;
-        }
-
-        SyncBandsFromAssignments();
-    }
-
-    private string GetColumnBand(string fieldName)
-    {
-        return columnBandAssignments.TryGetValue(fieldName, out var bandId) ? bandId : string.Empty;
-    }
-
-    private void SyncBandsFromAssignments()
-    {
-        foreach (var band in bandLayout.Bands)
-        {
-            band.Columns = columnDefinitions
-                .Where(column => columnBandAssignments.TryGetValue(column.FieldName, out var bandId) && bandId == band.Id)
-                .Select(column => column.FieldName)
-                .ToList();
-        }
-
-        StateHasChanged();
-    }
-
-    private void UpdateBandOptions()
-    {
-        bandOptions = new List<BandOption> { new() { Id = string.Empty, Caption = "Ohne Band" } };
-        bandOptions.AddRange(bandLayout.Bands.Select(band => new BandOption { Id = band.Id, Caption = band.Caption }));
-    }
-
-    private BandLayout NormalizeBandLayout(BandLayout? layout)
-    {
-        layout ??= new BandLayout();
-        layout.Bands ??= new List<BandDefinition>();
-        layout.ColumnOrder ??= new List<string>();
-        layout.ColumnWidths ??= new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
-        foreach (var band in layout.Bands)
-        {
-            if (string.IsNullOrWhiteSpace(band.Id))
-            {
-                band.Id = Guid.NewGuid().ToString("N");
-            }
-
-            if (string.IsNullOrWhiteSpace(band.Caption))
-            {
-                band.Caption = "Band";
-            }
-
-            band.Columns = band.Columns?.Where(columnLookup.ContainsKey).ToList() ?? new List<string>();
-        }
-
-        return layout;
-    }
-
-    private Dictionary<string, string> BuildAssignmentsFromLayout(BandLayout layout)
-    {
-        var assignments = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
-        foreach (var band in layout.Bands)
-        {
-            foreach (var column in band.Columns)
-            {
-                assignments[column] = band.Id;
-            }
-        }
-
-        return assignments;
-    }
-
-    private RenderFragment RenderColumns() => builder =>
-    {
-        var seq = 0;
-        builder.OpenComponent<DxGridCommandColumn>(seq++);
-        builder.AddAttribute(seq++, "Width", "120px");
-        builder.CloseComponent();
-
-        var grouped = bandLayout.Bands.SelectMany(band => band.Columns).ToHashSet(StringComparer.OrdinalIgnoreCase);
-        foreach (var column in columnDefinitions.Where(column => !grouped.Contains(column.FieldName)))
-        {
-            BuildDataColumn(builder, ref seq, column);
-        }
-
-        foreach (var band in bandLayout.Bands)
-        {
-            if (band.Columns.Count == 0)
-            {
-                continue;
-            }
-
-            builder.OpenComponent<DxGridBandColumn>(seq++);
-            builder.AddAttribute(seq++, "Caption", band.Caption);
-            builder.AddAttribute(seq++, "Columns", (RenderFragment)(bandBuilder =>
-            {
-                var bandSeq = 0;
-                foreach (var columnName in band.Columns)
-                {
-                    if (columnLookup.TryGetValue(columnName, out var column))
-                    {
-                        BuildDataColumn(bandBuilder, ref bandSeq, column);
-                    }
-                }
-            }));
-            builder.CloseComponent();
-        }
-    };
-
-    private void BuildDataColumn(RenderTreeBuilder builder, ref int seq, ColumnDefinition column)
-    {
-        builder.OpenComponent<DxGridDataColumn>(seq++);
-        builder.AddAttribute(seq++, "FieldName", column.FieldName);
-        builder.AddAttribute(seq++, "Caption", column.Caption);
-        if (!string.IsNullOrWhiteSpace(column.Width))
-        {
-            builder.AddAttribute(seq++, "Width", column.Width);
-        }
-
-        if (!string.IsNullOrWhiteSpace(column.DisplayFormat))
-        {
-            builder.AddAttribute(seq++, "DisplayFormat", column.DisplayFormat);
-        }
-
-        if (column.ReadOnly)
-        {
-            builder.AddAttribute(seq++, "ReadOnly", true);
-        }
-
-        if (string.Equals(column.FieldName, nameof(CatalogReadDto.AddedWhen), StringComparison.OrdinalIgnoreCase))
-        {
-            builder.AddAttribute(seq++, "FilterRowCellTemplate", BuildAddedWhenFilterTemplate());
-        }
-        else if (string.Equals(column.FieldName, nameof(CatalogReadDto.ChangedWhen), StringComparison.OrdinalIgnoreCase))
-        {
-            builder.AddAttribute(seq++, "FilterRowCellTemplate", BuildChangedWhenFilterTemplate());
-        }
-
-        builder.CloseComponent();
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildAddedWhenFilterTemplate()
-    {
-        return BuildDateFilterTemplate(
-            () => addedWhenFilterValue,
-            value => addedWhenFilterValue = value,
-            () => addedWhenFilterOperator,
-            value => addedWhenFilterOperator = value);
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildChangedWhenFilterTemplate()
-    {
-        return BuildDateFilterTemplate(
-            () => changedWhenFilterValue,
-            value => changedWhenFilterValue = value,
-            () => changedWhenFilterOperator,
-            value => changedWhenFilterOperator = value);
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildDateFilterTemplate(
-        Func<DateTime?> getValue,
-        Action<DateTime?> setValue,
-        Func<string> getOperator,
-        Action<string> setOperator)
-    {
-        return context => builder =>
-        {
-            var seq = 0;
-            builder.OpenElement(seq++, "div");
-            builder.AddAttribute(seq++, "class", "filter-row-cell");
-
-            builder.OpenComponent<DxComboBox<FilterOperatorOption, string>>(seq++);
-            builder.AddAttribute(seq++, "Data", filterOperators);
-            builder.AddAttribute(seq++, "TextFieldName", "Text");
-            builder.AddAttribute(seq++, "ValueFieldName", "Value");
-            builder.AddAttribute(seq++, "Value", getOperator());
-            builder.AddAttribute(seq++, "ValueChanged", EventCallback.Factory.Create<string>(this, value =>
-            {
-                setOperator(value);
-                UpdateFilterCriteria(context, value, getValue());
-            }));
-            builder.AddAttribute(seq++, "CssClass", "filter-operator");
-            builder.CloseComponent();
-
-            builder.OpenComponent<DxDateEdit<DateTime?>>(seq++);
-            builder.AddAttribute(seq++, "Date", getValue());
-            builder.AddAttribute(seq++, "DateChanged", EventCallback.Factory.Create<DateTime?>(this, value =>
-            {
-                setValue(value);
-                UpdateFilterCriteria(context, getOperator(), value);
-            }));
-            builder.AddAttribute(seq++, "ClearButtonDisplayMode", DataEditorClearButtonDisplayMode.Auto);
-            builder.AddAttribute(seq++, "CssClass", "filter-value");
-            builder.CloseComponent();
-
-            builder.CloseElement();
-        };
-    }
-
-    private void UpdateFilterCriteria(GridDataColumnFilterRowCellTemplateContext context, string op, DateTime? value)
-    {
-        if (!value.HasValue)
-        {
-            context.FilterCriteria = null;
-            return;
-        }
-
-        var prop = new OperandProperty(context.DataColumn.FieldName);
-        var date = value.Value.Date;
-        context.FilterCriteria = op switch
-        {
-            "=" => new GroupOperator(GroupOperatorType.And, prop >= date, prop < date.AddDays(1)),
-            "<" => prop < date,
-            "<=" => prop < date.AddDays(1),
-            ">" => prop >= date.AddDays(1),
-            ">=" => prop >= date,
-            _ => prop == date
-        };
-    }
-
-    private sealed class BandLayout
-    {
-        public List<BandDefinition> Bands { get; set; } = new();
-        public List<string> ColumnOrder { get; set; } = new();
-        public Dictionary<string, string?> ColumnWidths { get; set; } = new(StringComparer.OrdinalIgnoreCase);
-        public GridPersistentLayout? GridLayout { get; set; }
-    }
-
-    private sealed class BandDefinition
-    {
-        public string Id { get; set; } = string.Empty;
-        public string Caption { get; set; } = string.Empty;
-        public List<string> Columns { get; set; } = new();
-    }
-
-    private sealed class BandOption
-    {
-        public string Id { get; set; } = string.Empty;
-        public string Caption { get; set; } = string.Empty;
-    }
-
-    private sealed class ColumnDefinition
-    {
-        public string FieldName { get; init; } = string.Empty;
-        public string Caption { get; init; } = string.Empty;
-        public string? Width { get; set; }
-        public string? DisplayFormat { get; init; }
-        public bool ReadOnly { get; init; }
-        public ColumnFilterType FilterType { get; init; }
-    }
-
-    private enum ColumnFilterType
-    {
-        Text,
-        Date
-    }
-
-    private sealed class CatalogEditModel
-    {
-        public int Guid { get; set; }
-        public string CatTitle { get; set; } = string.Empty;
-        public string CatString { get; set; } = string.Empty;
-        public int UpdateProcedure { get; set; }
-        public string OriginalCatTitle { get; set; } = string.Empty;
-        public bool IsNew { get; set; }
-    }
-
-    private sealed class ProcedureOption
-    {
-        public int Value { get; set; }
-        public string Text { get; set; } = string.Empty;
-    }
-
-    private sealed class FilterOperatorOption
-    {
-        public string Value { get; set; } = string.Empty;
-        public string Text { get; set; } = string.Empty;
-    }
-}
--- a/DbFirst.BlazorWasm/Components/MassDataGrid.razor
+++ b/DbFirst.BlazorWasm/Components/MassDataGrid.razor
--- a/DbFirst.BlazorWasm/DbFirst.BlazorWasm.csproj
+++ b/DbFirst.BlazorWasm/DbFirst.BlazorWasm.csproj
@@ -1,23 +0,0 @@
-<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">
-
-  <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
-    <Nullable>enable</Nullable>
-    <ImplicitUsings>enable</ImplicitUsings>
-  </PropertyGroup>
-
-  <ItemGroup>
-    <PackageReference Include="DevExpress.Blazor" Version="25.2.3" />
-    <PackageReference Include="DevExpress.Blazor.Dashboard" Version="25.2.3" />
-    <PackageReference Include="DevExpress.Blazor.Themes" Version="25.2.3" />
-    <PackageReference Include="DevExpress.Blazor.Themes.Fluent" Version="25.2.3" />
-    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="8.0.22" />
-    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="8.0.22" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="8.0.22" />
-  </ItemGroup>
-
-  <ItemGroup>
-    <Folder Include="wwwroot\sample-data\" />
-  </ItemGroup>
-
-</Project>
--- a/DbFirst.BlazorWasm/Layout/MainLayout.razor
+++ b/DbFirst.BlazorWasm/Layout/MainLayout.razor
@@ -1,19 +0,0 @@
-@* Definiert das Hauptlayout der Anwendung.
-   Enthält die Navigationsleiste und den Hauptinhalt. *@
-
-@inherits LayoutComponentBase
-<div class="page">
-    <div class="sidebar">
-        <NavMenu /> <!-- Einbindung der Navigationsleiste -->
-    </div>
-
-    <main>
-        <div class="top-row px-4">
-            <a href="https://learn.microsoft.com/aspnet/core/" target="_blank">About</a>
-        </div>
-
-        <article class="content px-4">
-            @Body <!-- Platzhalter für den Seiteninhalt -->
-        </article>
-    </main>
-</div>
--- a/DbFirst.BlazorWasm/Layout/MainLayout.razor.css
+++ b/DbFirst.BlazorWasm/Layout/MainLayout.razor.css
@@ -1,77 +0,0 @@
-.page {
-    position: relative;
-    display: flex;
-    flex-direction: column;
-}
-
-main {
-    flex: 1;
-}
-
-.sidebar {
-    background-image: linear-gradient(180deg, rgb(5, 39, 103) 0%, #3a0647 70%);
-}
-
-.top-row {
-    background-color: #f7f7f7;
-    border-bottom: 1px solid #d6d5d5;
-    justify-content: flex-end;
-    height: 3.5rem;
-    display: flex;
-    align-items: center;
-}
-
-    .top-row ::deep a, .top-row ::deep .btn-link {
-        white-space: nowrap;
-        margin-left: 1.5rem;
-        text-decoration: none;
-    }
-
-    .top-row ::deep a:hover, .top-row ::deep .btn-link:hover {
-        text-decoration: underline;
-    }
-
-    .top-row ::deep a:first-child {
-        overflow: hidden;
-        text-overflow: ellipsis;
-    }
-
-@media (max-width: 640.98px) {
-    .top-row {
-        justify-content: space-between;
-    }
-
-    .top-row ::deep a, .top-row ::deep .btn-link {
-        margin-left: 0;
-    }
-}
-
-@media (min-width: 641px) {
-    .page {
-        flex-direction: row;
-    }
-
-    .sidebar {
-        width: 250px;
-        height: 100vh;
-        position: sticky;
-        top: 0;
-    }
-
-    .top-row {
-        position: sticky;
-        top: 0;
-        z-index: 1;
-    }
-
-    .top-row.auth ::deep a:first-child {
-        flex: 1;
-        text-align: right;
-        width: 0;
-    }
-
-    .top-row, article {
-        padding-left: 2rem !important;
-        padding-right: 1.5rem !important;
-    }
-}
--- a/DbFirst.BlazorWasm/Layout/NavMenu.razor
+++ b/DbFirst.BlazorWasm/Layout/NavMenu.razor
@@ -1,48 +0,0 @@
-@* Definiert die Navigationsleiste, die Links zu verschiedenen Seiten der Anwendung enthält. *@
-
-<div class="top-row ps-3 navbar navbar-dark">
-    <div class="container-fluid">
-        <a class="navbar-brand" href="">DbFirst.BlazorWasm</a>
-        <button title="Navigation menu" class="navbar-toggler" @onclick="ToggleNavMenu">
-            <span class="navbar-toggler-icon"></span>
-        </button>
-    </div>
-</div>
-
-<div class="@NavMenuCssClass nav-scrollable" @onclick="ToggleNavMenu">
-    <nav class="flex-column">
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
-                <span class="bi bi-house-door-fill-nav-menu" aria-hidden="true"></span> Home
-            </NavLink>
-        </div>
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="catalogs">
-                <span class="bi bi-collection-nav-menu" aria-hidden="true"></span> Catalogs
-            </NavLink>
-        </div>
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="dashboards">
-                <span class="bi bi-speedometer-nav-menu" aria-hidden="true"></span> Dashboards
-            </NavLink>
-        </div>
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="massdata">
-                <span class="bi bi-table-nav-menu" aria-hidden="true"></span> MassData
-            </NavLink>
-        </div>
-    </nav>
-</div>
-
-@code {
-    private bool collapseNavMenu = true;
-
-    // CSS-Klasse für die Navigation, die den Zustand (eingeklappt/ausgeklappt) steuert.
-    private string? NavMenuCssClass => collapseNavMenu ? "collapse" : null;
-
-    // Methode zum Umschalten des Navigationsmenüs.
-    private void ToggleNavMenu()
-    {
-        collapseNavMenu = !collapseNavMenu;
-    }
-}
--- a/DbFirst.BlazorWasm/Layout/NavMenu.razor.css
+++ b/DbFirst.BlazorWasm/Layout/NavMenu.razor.css
@@ -1,95 +0,0 @@
-.navbar-toggler {
-    background-color: rgba(255, 255, 255, 0.1);
-}
-
-.top-row {
-    height: 3.5rem;
-    background-color: rgba(0,0,0,0.4);
-}
-
-.navbar-brand {
-    font-size: 1.1rem;
-}
-
-.bi {
-    display: inline-block;
-    position: relative;
-    width: 1.25rem;
-    height: 1.25rem;
-    margin-right: 0.75rem;
-    top: -1px;
-    background-size: cover;
-}
-
-.bi-house-door-fill-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-house-door-fill' viewBox='0 0 16 16'%3E%3Cpath d='M6.5 14.5v-3.505c0-.245.25-.495.5-.495h2c.25 0 .5.25.5.5v3.5a.5.5 0 0 0 .5.5h4a.5.5 0 0 0 .5-.5v-7a.5.5 0 0 0-.146-.354L13 5.793V2.5a.5.5 0 0 0-.5-.5h-1a.5.5 0 0 0-.5.5v1.293L8.354 1.146a.5.5 0 0 0-.708 0l-6 6A.5.5 0 0 0 1.5 7.5v7a.5.5 0 0 0 .5.5h4a.5.5 0 0 0 .5-.5Z'/%3E%3C/svg%3E");
-}
-
-.bi-plus-square-fill-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-plus-square-fill' viewBox='0 0 16 16'%3E%3Cpath d='M2 0a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V2a2 2 0 0 0-2-2H2zm6.5 4.5v3h3a.5.5 0 0 1 0 1h-3v3a.5.5 0 0 1-1 0v-3h-3a.5.5 0 0 1 0-1h3v-3a.5.5 0 0 1 1 0z'/%3E%3C/svg%3E");
-}
-
-.bi-list-nested-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-list-nested' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M4.5 11.5A.5.5 0 0 1 5 11h10a.5.5 0 0 1 0 1H5a.5.5 0 0 1-.5-.5zm-2-4A.5.5 0 0 1 3 7h10a.5.5 0 0 1 0 1H3a.5.5 0 0 1-.5-.5zm-2-4A.5.5 0 0 1 1 3h10a.5.5 0 0 1 0 1H1a.5.5 0 0 1-.5-.5z'/%3E%3C/svg%3E");
-}
-
-.bi-collection-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M2 3a.5.5 0 0 1 .5-.5h11a.5.5 0 0 1 .5.5v1H2V3z'/%3E%3Cpath d='M2 5h12v8a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5z'/%3E%3C/svg%3E");
-}
-
-.bi-speedometer-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M1 11a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H2a1 1 0 0 0-1 1v4zm5 0a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V3a1 1 0 0 0-1-1H7a1 1 0 0 0-1 1v8zm5 0a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V9a1 1 0 0 0-1-1h-2a1 1 0 0 0-1 1v2z'/%3E%3C/svg%3E");
-}
-
-.bi-table-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M1 2a1 1 0 0 1 1-1h12a1 1 0 0 1 1 1v12a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V2zm1 1v2h12V3H2zm12 3H2v2h12V6zm0 3H2v2h12V9zm0 3H2v1h12v-1z'/%3E%3C/svg%3E");
-}
-
-.nav-item {
-    font-size: 0.9rem;
-    padding-bottom: 0.5rem;
-}
-
-    .nav-item:first-of-type {
-        padding-top: 1rem;
-    }
-
-    .nav-item:last-of-type {
-        padding-bottom: 1rem;
-    }
-
-    .nav-item ::deep a {
-        color: #d7d7d7;
-        border-radius: 4px;
-        height: 3rem;
-        display: flex;
-        align-items: center;
-        line-height: 3rem;
-    }
-
-.nav-item ::deep a.active {
-    background-color: rgba(255,255,255,0.37);
-    color: white;
-}
-
-.nav-item ::deep a:hover {
-    background-color: rgba(255,255,255,0.1);
-    color: white;
-}
-
-@media (min-width: 641px) {
-    .navbar-toggler {
-        display: none;
-    }
-
-    .collapse {
-        /* Never collapse the sidebar for wide screens */
-        display: block;
-    }
-    
-    .nav-scrollable {
-        /* Allow sidebar to scroll for tall menus */
-        height: calc(100vh - 3.5rem);
-        overflow-y: auto;
-    }
-}
--- a/DbFirst.BlazorWasm/Models/CatalogWriteDto.cs
+++ b/DbFirst.BlazorWasm/Models/CatalogWriteDto.cs
@@ -1,8 +0,0 @@
-namespace DbFirst.BlazorWasm.Models;
-
-public class CatalogWriteDto
-{
-    public string CatTitle { get; set; } = string.Empty;
-    public string CatString { get; set; } = string.Empty;
-    public int UpdateProcedure { get; set; } = 0; // 0 = Update, 1 = Save
-}
--- a/DbFirst.BlazorWasm/Models/DashboardInfoDto.cs
+++ b/DbFirst.BlazorWasm/Models/DashboardInfoDto.cs
@@ -1,7 +0,0 @@
-namespace DbFirst.BlazorWasm.Models;
-
-public class DashboardInfoDto
-{
-    public string Id { get; set; } = string.Empty;
-    public string Name { get; set; } = string.Empty;
-}
--- a/DbFirst.BlazorWasm/Models/MassDataReadDto.cs
+++ b/DbFirst.BlazorWasm/Models/MassDataReadDto.cs
@@ -1,12 +0,0 @@
-namespace DbFirst.BlazorWasm.Models;
-
-public class MassDataReadDto
-{
-    public int Id { get; set; }
-    public string CustomerName { get; set; } = string.Empty;
-    public decimal Amount { get; set; }
-    public string Category { get; set; } = string.Empty;
-    public bool StatusFlag { get; set; }
-    public DateTime AddedWhen { get; set; }
-    public DateTime? ChangedWhen { get; set; }
-}
--- a/DbFirst.BlazorWasm/Pages/Catalogs.razor
+++ b/DbFirst.BlazorWasm/Pages/Catalogs.razor
@@ -1,7 +0,0 @@
-@page "/catalogs"
-
-<PageTitle>Catalogs</PageTitle>
-
-<h1>Catalogs</h1>
-
-<CatalogsGrid />
--- a/DbFirst.BlazorWasm/Pages/Dashboard.razor
+++ b/DbFirst.BlazorWasm/Pages/Dashboard.razor
@@ -1,163 +0,0 @@
-@page "/dashboard"
-@page "/dashboards/{DashboardId?}"
-@implements IAsyncDisposable
-@inject Microsoft.Extensions.Configuration.IConfiguration Configuration
-@inject NavigationManager Navigation
-@inject DashboardApiClient DashboardApi
-
-<style>
-    .dashboard-shell {
-        display: flex;
-        gap: 0;
-        min-height: 800px;
-        border: 1px solid #e6e6e6;
-        border-radius: 6px;
-        overflow: hidden;
-        background: #fff;
-    }
-    .dashboard-nav {
-        width: 220px;
-        border-right: 1px solid #e6e6e6;
-        background: #fafafa;
-    }
-    .dashboard-nav-title {
-        padding: 0.75rem 1rem 0.5rem;
-        font-size: 0.7rem;
-        text-transform: uppercase;
-        letter-spacing: 0.08em;
-        color: #6c757d;
-        font-weight: 600;
-    }
-    .dashboard-nav-link {
-        display: block;
-        padding: 0.55rem 1rem;
-        color: inherit;
-        text-decoration: none;
-    }
-    .dashboard-nav-link.active {
-        background: #e9ecef;
-        font-weight: 600;
-    }
-    .dashboard-content {
-        flex: 1;
-        min-width: 0;
-        padding: 1rem;
-    }
-</style>
-
-<PageTitle>Dashboards</PageTitle>
-
-<div class="dashboard-shell">
-    <aside class="dashboard-nav">
-        <div class="dashboard-nav-title">Dashboards</div>
-        @if (dashboards.Count == 0)
-        {
-            <div class="px-3 py-2 text-muted">Keine Dashboards vorhanden.</div>
-        }
-        else
-        {
-            @foreach (var dashboard in dashboards)
-            {
-                <NavLink class="dashboard-nav-link" href="@($"dashboards/{dashboard.Id}?mode={(IsDesigner ? "designer" : "viewer")}")">@dashboard.Name</NavLink>
-            }
-        }
-    </aside>
-    <section class="dashboard-content">
-        <div class="mb-3">
-            <DxButton RenderStyle="ButtonRenderStyle.Primary" Click="@ToggleMode">
-                @(IsDesigner ? "Zum Viewer wechseln" : "Zum Designer wechseln")
-            </DxButton>
-        </div>
-        <DxDashboard @key="DashboardKey" Endpoint="@DashboardEndpoint" InitialDashboardId="@SelectedDashboardId" WorkingMode="@CurrentMode" style="width: 100%; height: 800px;">
-        </DxDashboard>
-    </section>
-</div>
-
-@code {
-    [Parameter] public string? DashboardId { get; set; }
-    [SupplyParameterFromQuery] public string? Mode { get; set; }
-
-    private readonly List<DashboardInfoDto> dashboards = new();
-    private HubConnection? _hubConnection;
-
-    private bool IsDesigner => !string.Equals(Mode, "viewer", StringComparison.OrdinalIgnoreCase);
-    private WorkingMode CurrentMode => IsDesigner ? WorkingMode.Designer : WorkingMode.ViewerOnly;
-    private string SelectedDashboardId { get; set; } = string.Empty;
-    private string DashboardKey => $"{SelectedDashboardId}-{(IsDesigner ? "designer" : "viewer")}";
-
-    private string DashboardEndpoint => $"{Configuration["ApiBaseUrl"]?.TrimEnd('/')}/api/dashboard";
-    private string HubEndpoint => $"{Configuration["ApiBaseUrl"]?.TrimEnd('/')}/hubs/dashboards";
-
-    protected override async Task OnInitializedAsync()
-    {
-        await RefreshDashboards();
-
-        _hubConnection = new HubConnectionBuilder()
-            .WithUrl(HubEndpoint)
-            .WithAutomaticReconnect()
-            .Build();
-
-        _hubConnection.On("DashboardsChanged", async () =>
-        {
-            await RefreshDashboards();
-        });
-
-        await _hubConnection.StartAsync();
-    }
-
-    protected override async Task OnParametersSetAsync()
-    {
-        if (dashboards.Count == 0)
-        {
-            await RefreshDashboards();
-        }
-
-        var requestedId = string.IsNullOrWhiteSpace(DashboardId) || string.Equals(DashboardId, "default", StringComparison.OrdinalIgnoreCase)
-            ? null
-            : DashboardId;
-
-        var resolved = !string.IsNullOrWhiteSpace(requestedId)
-            ? dashboards.FirstOrDefault(d => string.Equals(d.Id, requestedId, StringComparison.OrdinalIgnoreCase))
-            : dashboards.FirstOrDefault(d => string.Equals(d.Id, "DefaultDashboard", StringComparison.OrdinalIgnoreCase))
-              ?? dashboards.FirstOrDefault();
-
-        if (resolved == null)
-        {
-            return;
-        }
-
-        SelectedDashboardId = resolved.Id;
-
-        if (!string.Equals(DashboardId, resolved.Id, StringComparison.OrdinalIgnoreCase))
-        {
-            Navigation.NavigateTo($"dashboards/{resolved.Id}?mode={(IsDesigner ? "designer" : "viewer")}", replace: true);
-        }
-    }
-
-    private void ToggleMode()
-    {
-        var targetMode = IsDesigner ? "viewer" : "designer";
-        Navigation.NavigateTo($"dashboards/{SelectedDashboardId}?mode={targetMode}", replace: true);
-    }
-
-    private async Task RefreshDashboards()
-    {
-        var latest = await DashboardApi.GetAllAsync();
-        if (latest.Count == dashboards.Count && latest.All(d => dashboards.Any(x => x.Id == d.Id && x.Name == d.Name)))
-        {
-            return;
-        }
-
-        dashboards.Clear();
-        dashboards.AddRange(latest);
-        await InvokeAsync(StateHasChanged);
-    }
-
-    public async ValueTask DisposeAsync()
-    {
-        if (_hubConnection != null)
-        {
-            await _hubConnection.DisposeAsync();
-        }
-    }
-}
--- a/DbFirst.BlazorWasm/Pages/Home.razor
+++ b/DbFirst.BlazorWasm/Pages/Home.razor
@@ -1,7 +0,0 @@
-@page "/"
-
-<PageTitle>Home</PageTitle>
-
-<h1>Db First approach</h1>
-
-This is a Blazor WebAssembly application demonstrating the Database First approach using DevExpress components.
--- a/DbFirst.BlazorWasm/Pages/Massdata.razor
+++ b/DbFirst.BlazorWasm/Pages/Massdata.razor
@@ -1,7 +0,0 @@
-@page "/massdata"
-
-<PageTitle>MassData</PageTitle>
-
-<h1>MassData</h1>
-
-<MassDataGrid />
--- a/DbFirst.BlazorWasm/Program.cs
+++ b/DbFirst.BlazorWasm/Program.cs
@@ -1,24 +0,0 @@
-/* Initialisiert die Blazor WebAssembly-Anwendung.
-   Registriert Root-Komponenten 
-   Konfiguriert Abhängigkeiten */
-
-using Microsoft.AspNetCore.Components.Web;
-using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
-using DbFirst.BlazorWasm;
-using DbFirst.BlazorWasm.Services;
-using DevExpress.Blazor;
-
-var builder = WebAssemblyHostBuilder.CreateDefault(args);
-builder.RootComponents.Add<App>("#app");
-builder.RootComponents.Add<HeadOutlet>("head::after");
-
-builder.Services.AddDevExpressBlazor();
-
-var apiBaseUrl = builder.Configuration["ApiBaseUrl"] ?? builder.HostEnvironment.BaseAddress;
-builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(apiBaseUrl) });
-builder.Services.AddScoped<CatalogApiClient>();
-builder.Services.AddScoped<DashboardApiClient>();
-builder.Services.AddScoped<MassDataApiClient>();
-builder.Services.AddScoped<LayoutApiClient>();
-
-await builder.Build().RunAsync();
--- a/DbFirst.BlazorWasm/Properties/launchSettings.json
+++ b/DbFirst.BlazorWasm/Properties/launchSettings.json
@@ -1,41 +0,0 @@
-{
-  "$schema": "http://json.schemastore.org/launchsettings.json",
-  "iisSettings": {
-    "windowsAuthentication": false,
-    "anonymousAuthentication": true,
-    "iisExpress": {
-      "applicationUrl": "http://localhost:12804",
-      "sslPort": 44394
-    }
-  },
-  "profiles": {
-    "http": {
-      "commandName": "Project",
-      "dotnetRunMessages": true,
-      "launchBrowser": true,
-      "inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}",
-      "applicationUrl": "http://localhost:5101",
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    },
-    "https": {
-      "commandName": "Project",
-      "dotnetRunMessages": true,
-      "launchBrowser": true,
-      "inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}",
-      "applicationUrl": "https://localhost:7276;http://localhost:5101",
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    },
-    "IIS Express": {
-      "commandName": "IISExpress",
-      "launchBrowser": true,
-      "inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}",
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    }
-  }
-}
--- a/DbFirst.BlazorWasm/Services/CatalogApiClient.cs
+++ b/DbFirst.BlazorWasm/Services/CatalogApiClient.cs
@@ -1,148 +0,0 @@
-/* Kapselt die Kommunikation mit der API für den Catalog-Endpunkt.
-   Bietet Methoden für CRUD-Operationen auf Catalog-Daten */
-
-using System.Net;
-using System.Net.Http.Json;
-using System.Text.Json;
-using DbFirst.BlazorWasm.Models;
-
-namespace DbFirst.BlazorWasm.Services;
-
-public class CatalogApiClient
-{
-    private readonly HttpClient _httpClient;
-    private const string Endpoint = "api/catalogs";
-
-    public CatalogApiClient(HttpClient httpClient)
-    {
-        _httpClient = httpClient;
-    }
-
-    public async Task<List<CatalogReadDto>> GetAllAsync()
-    {
-        var result = await _httpClient.GetFromJsonAsync<List<CatalogReadDto>>(Endpoint);
-        return result ?? new List<CatalogReadDto>();
-    }
-
-    public async Task<CatalogReadDto?> GetByIdAsync(int id)
-    {
-        return await _httpClient.GetFromJsonAsync<CatalogReadDto>($"{Endpoint}/{id}");
-    }
-
-    public async Task<ApiResult<CatalogReadDto?>> CreateAsync(CatalogWriteDto dto)
-    {
-        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto);
-        if (response.IsSuccessStatusCode)
-        {
-            var payload = await response.Content.ReadFromJsonAsync<CatalogReadDto>();
-            return ApiResult<CatalogReadDto?>.Ok(payload);
-        }
-
-        var error = await ReadErrorAsync(response);
-        return ApiResult<CatalogReadDto?>.Fail(error);
-    }
-
-    public async Task<ApiResult<bool>> UpdateAsync(int id, CatalogWriteDto dto)
-    {
-        var response = await _httpClient.PutAsJsonAsync($"{Endpoint}/{id}", dto);
-        if (response.IsSuccessStatusCode)
-        {
-            return ApiResult<bool>.Ok(true);
-        }
-
-        var error = await ReadErrorAsync(response);
-        return ApiResult<bool>.Fail(error);
-    }
-
-    public async Task<ApiResult<bool>> DeleteAsync(int id)
-    {
-        var response = await _httpClient.DeleteAsync($"{Endpoint}/{id}");
-        if (response.IsSuccessStatusCode)
-        {
-            return ApiResult<bool>.Ok(true);
-        }
-
-        var error = await ReadErrorAsync(response);
-        return ApiResult<bool>.Fail(error);
-    }
-
-    private static async Task<string> ReadErrorAsync(HttpResponseMessage response)
-    {
-        // Liest und analysiert Fehlerdetails aus der API-Antwort.
-        // Gibt eine benutzerfreundliche Fehlermeldung zurück.
-
-        string? problemTitle = null;
-        string? problemDetail = null;
-
-        try
-        {
-            var problem = await response.Content.ReadFromJsonAsync<ProblemDetailsDto>();
-            if (problem != null)
-            {
-                problemTitle = problem.Title;
-                problemDetail = problem.Detail ?? problem.Type;
-            }
-        }
-        catch
-        {
-            // ignore parse errors
-        }
-
-        var status = response.StatusCode;
-        var reason = response.ReasonPhrase;
-        var body = await response.Content.ReadAsStringAsync();
-
-        string detail = problemDetail;
-        if (string.IsNullOrWhiteSpace(detail) && !string.IsNullOrWhiteSpace(body))
-        {
-            detail = body;
-        }
-
-        // Friendly overrides
-        if (status == HttpStatusCode.Conflict)
-        {
-            return "Datensatz existiert bereits. Bitte wählen Sie einen anderen Titel.";
-        }
-        if (status == HttpStatusCode.BadRequest && (detail?.Contains("CatTitle cannot be changed", StringComparison.OrdinalIgnoreCase) ?? false))
-        {
-            return "Titel kann nicht geändert werden.";
-        }
-
-        return status switch
-        {
-            HttpStatusCode.BadRequest => $"Eingabe ungültig{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.NotFound => $"Nicht gefunden{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Conflict => $"Konflikt{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Unauthorized => $"Nicht autorisiert{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Forbidden => $"Nicht erlaubt{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.InternalServerError => $"Serverfehler{FormatSuffix(problemTitle, detail, reason)}",
-            _ => $"Fehler {(int)status} {reason ?? string.Empty}{FormatSuffix(problemTitle, detail, reason)}"
-        };
-    }
-
-    private static string FormatSuffix(string? title, string? detail, string? reason)
-    {
-        // Formatiert zusätzliche Informationen für Fehlermeldungen.
-        // Kombiniert Titel, Details und Grund in einer lesbaren Form.
-
-        var parts = new List<string>();
-        if (!string.IsNullOrWhiteSpace(title)) parts.Add(title);
-        if (!string.IsNullOrWhiteSpace(detail)) parts.Add(detail);
-        if (parts.Count == 0 && !string.IsNullOrWhiteSpace(reason)) parts.Add(reason);
-        if (parts.Count == 0) return string.Empty;
-        return ": " + string.Join(" | ", parts);
-    }
-}
-
-public record ApiResult<T>(bool Success, T? Value, string? Error)
-{
-    public static ApiResult<T> Ok(T? value) => new(true, value, null);
-    public static ApiResult<T> Fail(string? error) => new(false, default, error);
-}
-
-internal sealed class ProblemDetailsDto
-{
-    public string? Type { get; set; }
-    public string? Title { get; set; }
-    public string? Detail { get; set; }
-}
--- a/DbFirst.BlazorWasm/Services/DashboardApiClient.cs
+++ b/DbFirst.BlazorWasm/Services/DashboardApiClient.cs
@@ -1,21 +0,0 @@
-using System.Net.Http.Json;
-using DbFirst.BlazorWasm.Models;
-
-namespace DbFirst.BlazorWasm.Services;
-
-public class DashboardApiClient
-{
-    private readonly HttpClient _httpClient;
-    private const string Endpoint = "api/dashboard/dashboards";
-
-    public DashboardApiClient(HttpClient httpClient)
-    {
-        _httpClient = httpClient;
-    }
-
-    public async Task<List<DashboardInfoDto>> GetAllAsync()
-    {
-        var result = await _httpClient.GetFromJsonAsync<List<DashboardInfoDto>>(Endpoint);
-        return result ?? new List<DashboardInfoDto>();
-    }
-}
--- a/DbFirst.BlazorWasm/Services/LayoutApiClient.cs
+++ b/DbFirst.BlazorWasm/Services/LayoutApiClient.cs
@@ -1,64 +0,0 @@
-using System.Net.Http.Json;
-using DbFirst.BlazorWasm.Models;
-
-namespace DbFirst.BlazorWasm.Services;
-
-public class LayoutApiClient
-{
-    private readonly HttpClient _httpClient;
-    private const string Endpoint = "api/layouts";
-
-    public LayoutApiClient(HttpClient httpClient)
-    {
-        _httpClient = httpClient;
-    }
-
-    public async Task<LayoutDto?> GetAsync(string layoutType, string layoutKey, string userName)
-    {
-        var url = $"{Endpoint}?layoutType={Uri.EscapeDataString(layoutType)}&layoutKey={Uri.EscapeDataString(layoutKey)}&userName={Uri.EscapeDataString(userName)}";
-        var response = await _httpClient.GetAsync(url);
-        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
-        {
-            return null;
-        }
-
-        response.EnsureSuccessStatusCode();
-        return await response.Content.ReadFromJsonAsync<LayoutDto>();
-    }
-
-    public async Task<LayoutDto> UpsertAsync(LayoutDto dto)
-    {
-        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto);
-        if (!response.IsSuccessStatusCode)
-        {
-            var detail = await ReadErrorAsync(response);
-            throw new InvalidOperationException(detail);
-        }
-
-        var payload = await response.Content.ReadFromJsonAsync<LayoutDto>();
-        return payload ?? dto;
-    }
-
-    private static async Task<string> ReadErrorAsync(HttpResponseMessage response)
-    {
-        var body = await response.Content.ReadAsStringAsync();
-        if (!string.IsNullOrWhiteSpace(body))
-        {
-            return body;
-        }
-
-        return $"{(int)response.StatusCode} {response.ReasonPhrase}".Trim();
-    }
-
-    public async Task DeleteAsync(string layoutType, string layoutKey, string userName)
-    {
-        var url = $"{Endpoint}?layoutType={Uri.EscapeDataString(layoutType)}&layoutKey={Uri.EscapeDataString(layoutKey)}&userName={Uri.EscapeDataString(userName)}";
-        var response = await _httpClient.DeleteAsync(url);
-        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
-        {
-            return;
-        }
-
-        response.EnsureSuccessStatusCode();
-    }
-}
--- a/DbFirst.BlazorWasm/Services/MassDataApiClient.cs
+++ b/DbFirst.BlazorWasm/Services/MassDataApiClient.cs
@@ -1,63 +0,0 @@
-using System.Net.Http.Json;
-using DbFirst.BlazorWasm.Models;
-
-namespace DbFirst.BlazorWasm.Services;
-
-public class MassDataApiClient
-{
-    private readonly HttpClient _httpClient;
-    private const string Endpoint = "api/massdata";
-
-    public MassDataApiClient(HttpClient httpClient)
-    {
-        _httpClient = httpClient;
-    }
-
-    public async Task<int> GetCountAsync()
-    {
-        var result = await _httpClient.GetFromJsonAsync<int?>("api/massdata/count");
-        return result ?? 0;
-    }
-
-    public async Task<List<MassDataReadDto>> GetAllAsync(int? skip, int? take)
-    {
-        var query = new List<string>();
-        if (skip.HasValue)
-        {
-            query.Add($"skip={skip.Value}");
-        }
-        if (take.HasValue)
-        {
-            query.Add($"take={take.Value}");
-        }
-
-        var url = query.Count == 0 ? Endpoint : $"{Endpoint}?{string.Join("&", query)}";
-        var result = await _httpClient.GetFromJsonAsync<List<MassDataReadDto>>(url);
-        return result ?? new List<MassDataReadDto>();
-    }
-
-    public async Task<MassDataReadDto> UpsertAsync(MassDataWriteDto dto)
-    {
-        var response = await _httpClient.PostAsJsonAsync($"{Endpoint}/upsert", dto);
-        response.EnsureSuccessStatusCode();
-        var payload = await response.Content.ReadFromJsonAsync<MassDataReadDto>();
-        return payload ?? new MassDataReadDto();
-    }
-
-    public async Task<MassDataReadDto?> GetByCustomerNameAsync(string customerName)
-    {
-        if (string.IsNullOrWhiteSpace(customerName))
-        {
-            return null;
-        }
-
-        var response = await _httpClient.GetAsync($"{Endpoint}/{Uri.EscapeDataString(customerName)}");
-        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
-        {
-            return null;
-        }
-
-        response.EnsureSuccessStatusCode();
-        return await response.Content.ReadFromJsonAsync<MassDataReadDto>();
-    }
-}
--- a/DbFirst.BlazorWasm/_Imports.razor
+++ b/DbFirst.BlazorWasm/_Imports.razor
@@ -1,17 +0,0 @@
-@using System.Net.Http
-@using System.Net.Http.Json
-@using Microsoft.AspNetCore.Components.Forms
-@using Microsoft.AspNetCore.Components.Routing
-@using Microsoft.AspNetCore.Components.Web
-@using Microsoft.AspNetCore.Components.Web.Virtualization
-@using Microsoft.AspNetCore.Components.WebAssembly.Http
-@using Microsoft.JSInterop
-@using Microsoft.AspNetCore.SignalR.Client
-@using DbFirst.BlazorWasm
-@using DbFirst.BlazorWasm.Layout
-@using DbFirst.BlazorWasm.Models
-@using DbFirst.BlazorWasm.Services
-@using DbFirst.BlazorWasm.Components
-@using DevExpress.Blazor
-@using DevExpress.DashboardBlazor
-@using DevExpress.DashboardWeb
--- a/DbFirst.BlazorWasm/wwwroot/appsettings.json
+++ b/DbFirst.BlazorWasm/wwwroot/appsettings.json
@@ -1,3 +0,0 @@
-{
-  "ApiBaseUrl": "https://localhost:7204/"
-}
--- a/DbFirst.BlazorWasm/wwwroot/css/app.css
+++ b/DbFirst.BlazorWasm/wwwroot/css/app.css
@@ -1,103 +0,0 @@
-html, body {
-    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
-}
-
-h1:focus {
-    outline: none;
-}
-
-a, .btn-link {
-    color: #0071c1;
-}
-
-.btn-primary {
-    color: #fff;
-    background-color: #1b6ec2;
-    border-color: #1861ac;
-}
-
-.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
-  box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
-}
-
-.content {
-    padding-top: 1.1rem;
-}
-
-.valid.modified:not([type=checkbox]) {
-    outline: 1px solid #26b050;
-}
-
-.invalid {
-    outline: 1px solid red;
-}
-
-.validation-message {
-    color: red;
-}
-
-#blazor-error-ui {
-    background: lightyellow;
-    bottom: 0;
-    box-shadow: 0 -1px 2px rgba(0, 0, 0, 0.2);
-    display: none;
-    left: 0;
-    padding: 0.6rem 1.25rem 0.7rem 1.25rem;
-    position: fixed;
-    width: 100%;
-    z-index: 1000;
-}
-
-    #blazor-error-ui .dismiss {
-        cursor: pointer;
-        position: absolute;
-        right: 0.75rem;
-        top: 0.5rem;
-    }
-
-.blazor-error-boundary {
-    background: url(data:image/svg+xml;base64,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) no-repeat 1rem/1.8rem, #b32121;
-    padding: 1rem 1rem 1rem 3.7rem;
-    color: white;
-}
-
-    .blazor-error-boundary::after {
-        content: "An error has occurred."
-    }
-
-.loading-progress {
-    position: relative;
-    display: block;
-    width: 8rem;
-    height: 8rem;
-    margin: 20vh auto 1rem auto;
-}
-
-    .loading-progress circle {
-        fill: none;
-        stroke: #e0e0e0;
-        stroke-width: 0.6rem;
-        transform-origin: 50% 50%;
-        transform: rotate(-90deg);
-    }
-
-        .loading-progress circle:last-child {
-            stroke: #1b6ec2;
-            stroke-dasharray: calc(3.141 * var(--blazor-load-percentage, 0%) * 0.8), 500%;
-            transition: stroke-dasharray 0.05s ease-in-out;
-        }
-
-.loading-progress-text {
-    position: absolute;
-    text-align: center;
-    font-weight: bold;
-    inset: calc(20vh + 3.25rem) 0 auto 0.2rem;
-}
-
-    .loading-progress-text:after {
-        content: var(--blazor-load-percentage-text, "Loading");
-    }
-
-code {
-    color: #c02d76;
-}
--- a/DbFirst.BlazorWasm/wwwroot/css/bootstrap/bootstrap.min.css
+++ b/DbFirst.BlazorWasm/wwwroot/css/bootstrap/bootstrap.min.css
--- a/DbFirst.BlazorWasm/wwwroot/css/bootstrap/bootstrap.min.css.map
+++ b/DbFirst.BlazorWasm/wwwroot/css/bootstrap/bootstrap.min.css.map
--- a/DbFirst.BlazorWasm/wwwroot/favicon.png
+++ b/DbFirst.BlazorWasm/wwwroot/favicon.png
--- a/DbFirst.BlazorWasm/wwwroot/icon-192.png
+++ b/DbFirst.BlazorWasm/wwwroot/icon-192.png
--- a/DbFirst.BlazorWasm/wwwroot/index.html
+++ b/DbFirst.BlazorWasm/wwwroot/index.html
@@ -1,58 +0,0 @@
-<!--
-•	Ist der technische Einstiegspunkt der Blazor WebAssembly-Anwendung.
-•	Sie lädt die notwendigen Ressourcen (z. B. das Blazor-Skript blazor.webassembly.js)
-    und definiert den Platzhalter <div id="app">, in dem die Blazor-Komponenten gerendert werden.
-•	Ohne diese Datei könnte die Blazor-Anwendung nicht starten, da sie die Verbindung
-    zwischen der statischen HTML-Welt und der Blazor-Welt herstellt.
-    kurz: Startet die Anwendung und lädt die Blazor-Umgebung.
-    -->
-
-    <!DOCTYPE html>
-    <html lang="en">
-
-    <head>
-        <meta charset="utf-8" />
-        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-        <title>DbFirst.BlazorWasm</title>
-        <base href="/" />
-
-        <!-- Stylesheets für DevExpress und Bootstrap -->
-
-        <link href="_content/DevExpress.Blazor.Dashboard/ace.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/ace-theme-dreamweaver.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/ace-theme-ambiance.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/dx.light.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/dx-analytics.common.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/dx-analytics.light.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/dx-querybuilder.css" rel="stylesheet" />
-        <link href="_content/DevExpress.Blazor.Dashboard/dx-dashboard.light.min.css" rel="stylesheet" />
-
-        <link rel="stylesheet" href="css/bootstrap/bootstrap.min.css" />
-        <link rel="stylesheet" href="css/app.css" />
-
-        <link rel="icon" type="image/png" href="favicon.png" />
-        <link href="DbFirst.BlazorWasm.styles.css" rel="stylesheet" />
-    </head>
-
-    <body>
-        <!-- Einstiegspunkt der Blazor-Anwendung -->
-        <div id="app">
-            <svg class="loading-progress">
-                <circle r="40%" cx="50%" cy="50%" />
-                <circle r="40%" cx="50%" cy="50%" />
-            </svg>
-            <div class="loading-progress-text"></div>
-        </div>
-
-        <!-- Fehler-UI für unvorhergesehene Fehler -->
-        <div id="blazor-error-ui">
-            An unhandled error has occurred.
-            <a href="" class="reload">Reload</a>
-            <a class="dismiss">🗙</a>
-        </div>
-
-        <!-- Blazor WebAssembly-Skript -->
-        <script src="_framework/blazor.webassembly.js"></script>
-    </body>
-
-</html>
--- a/DbFirst.BlazorWebApp/AppSettings.cs
+++ b/DbFirst.BlazorWebApp/AppSettings.cs
@@ -0,0 +1,6 @@
+namespace DbFirst.BlazorWebApp;
+
+public class AppSettings
+{
+    public string ApiBaseUrl { get; set; } = string.Empty;
+}
--- a/DbFirst.BlazorWebApp/Components/App.razor
+++ b/DbFirst.BlazorWebApp/Components/App.razor
@@ -17,17 +17,21 @@
    <link href="_content/DevExpress.Blazor.Dashboard/dx-querybuilder.css" rel="stylesheet" />
    <link href="_content/DevExpress.Blazor.Dashboard/dx-dashboard.light.min.css" rel="stylesheet" />

-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes/bootstrap-external.bs5.min.css" />
-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes.Fluent/core.min.css" />
-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes.Fluent/global.min.css" />
-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes.Fluent/modes/light.min.css" />
-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes.Fluent/accents/blue.min.css" />
-    <link rel="stylesheet" href="_content/DevExpress.Blazor.Themes.Fluent/bootstrap/fluent-light.bs5.min.css" />
-
    <link rel="stylesheet" href="bootstrap/bootstrap.min.css" />
+    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons@1.11.3/font/bootstrap-icons.min.css" />
+
    <link rel="stylesheet" href="app.css" />
    <link rel="stylesheet" href="DbFirst.BlazorWebApp.styles.css" />
    <link rel="icon" type="image/png" href="favicon.png" />
+    <script src="js/size-manager.js"></script>
+    <script>
+        window.setDxDarkOverride = function (enabled) {
+            if (enabled)
+                document.documentElement.classList.add('dx-dark');
+            else
+                document.documentElement.classList.remove('dx-dark');
+        };
+    </script>
    <HeadOutlet />
 </head>

--- a/DbFirst.BlazorWebApp/Components/BandEditor.razor
+++ b/DbFirst.BlazorWebApp/Components/BandEditor.razor
@@ -0,0 +1,55 @@
+<div class="band-editor">
+    <button class="band-editor-toggle" @onclick="() => IsExpanded = !IsExpanded">
+        <span class="band-editor-toggle-icon @(IsExpanded ? "expanded" : "")">&#9658;</span>
+        <span>Layout</span>
+    </button>
+    @if (IsExpanded)
+    {
+        <div class="band-editor-body">
+            <div class="band-controls">
+                <DxButton Text="Band hinzufügen" Click="OnAddBand" />
+                <DxButton Text="Layout speichern" Click="OnSaveLayout" Enabled="@CanSave" />
+                <DxButton Text="Layout zurücksetzen" Click="OnResetLayout" />
+            </div>
+            @foreach (var band in Bands)
+            {
+                <div class="band-row">
+                    <DxTextBox Text="@band.Caption" TextChanged="@(value => OnBandCaptionChanged.InvokeAsync((band, value)))" />
+                    <DxButton Text="Entfernen" Click="@(() => OnRemoveBand.InvokeAsync(band))" />
+                </div>
+            }
+            <DxFormLayout CssClass="band-columns" ColCount="2">
+                @foreach (var column in Columns)
+                {
+                    <DxFormLayoutItem Caption="@column.Caption">
+                        <DxComboBox Data="@BandOptions"
+                                    TData="BandOption"
+                                    TValue="string"
+                                    TextFieldName="Caption"
+                                    ValueFieldName="Id"
+                                    Value="@GetColumnBand(column.FieldName)"
+                                    ValueChanged="@(value => OnColumnBandChanged.InvokeAsync((column.FieldName, value)))"
+                                    Width="100%" />
+                    </DxFormLayoutItem>
+                }
+            </DxFormLayout>
+        </div>
+    }
+</div>
+
+@code {
+    private bool IsExpanded { get; set; }
+
+    [Parameter, EditorRequired] public List<BandDefinition> Bands { get; set; } = new();
+    [Parameter, EditorRequired] public List<BandOption> BandOptions { get; set; } = new();
+    [Parameter, EditorRequired] public List<ColumnDefinition> Columns { get; set; } = new();
+    [Parameter, EditorRequired] public Func<string, string> GetColumnBand { get; set; } = _ => string.Empty;
+    [Parameter, EditorRequired] public bool CanSave { get; set; }
+
+    [Parameter] public EventCallback OnAddBand { get; set; }
+    [Parameter] public EventCallback OnSaveLayout { get; set; }
+    [Parameter] public EventCallback OnResetLayout { get; set; }
+    [Parameter] public EventCallback<BandDefinition> OnRemoveBand { get; set; }
+    [Parameter] public EventCallback<(BandDefinition Band, string Value)> OnBandCaptionChanged { get; set; }
+    [Parameter] public EventCallback<(string FieldName, string? BandId)> OnColumnBandChanged { get; set; }
+}
--- a/DbFirst.BlazorWebApp/Components/BandGridBase.cs
+++ b/DbFirst.BlazorWebApp/Components/BandGridBase.cs
@@ -0,0 +1,278 @@
+using DbFirst.BlazorWebApp.Models.Grid;
+using DbFirst.BlazorWebApp.Services;
+using DevExpress.Blazor;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Forms;
+using Microsoft.AspNetCore.Components.Rendering;
+
+namespace DbFirst.BlazorWebApp.Components;
+
+public abstract class BandGridBase<TItem> : ComponentBase
+{
+    [Inject] protected BandLayoutService BandLayoutService { get; set; } = default!;
+
+    // --- Abstract: jedes Grid definiert diese selbst ---
+    protected abstract string LayoutKey { get; }
+    protected abstract List<ColumnDefinition> ColumnDefinitions { get; }
+
+    // --- Band-Layout Felder ---
+    protected BandLayout bandLayout = new();
+    protected Dictionary<string, string> columnBandAssignments = new();
+    protected List<BandOption> bandOptions = new();
+    protected Dictionary<string, ColumnDefinition> columnLookup = new();
+    protected string? layoutUser;
+    protected bool gridLayoutApplied;
+    protected IGrid? gridRef;
+
+    // --- SizeMode ---
+    protected SizeMode _sizeMode = SizeMode.Medium;
+    protected static readonly List<SizeMode> _sizeModes = Enum.GetValues<SizeMode>().ToList();
+
+    protected string? errorMessage;
+    protected string? infoMessage;
+    protected bool isLoading;
+    protected bool hasLoaded;
+    protected EditContext? editContext;
+    protected ValidationMessageStore? validationMessageStore;
+    protected string popupHeaderText = "Edit";
+    protected int _focusedVisibleIndex;
+
+    private const string LayoutType = "GRID_BANDS";
+
+    // --- Lifecycle ---
+    protected async Task InitializeBandLayoutAsync()
+    {
+        columnLookup = ColumnDefinitions.ToDictionary(c => c.FieldName, StringComparer.OrdinalIgnoreCase);
+        layoutUser = await BandLayoutService.EnsureLayoutUserAsync();
+        bandLayout = await BandLayoutService.LoadBandLayoutAsync(LayoutType, LayoutKey, layoutUser, columnLookup);
+        columnBandAssignments = BandLayoutService.BuildAssignmentsFromLayout(bandLayout);
+        ApplyColumnLayoutFromStorage();
+        _sizeMode = bandLayout.SizeMode;
+        UpdateBandOptions();
+    }
+
+    protected async Task ApplyGridLayoutAfterRenderAsync()
+    {
+        if (!gridLayoutApplied && gridRef != null && bandLayout.GridLayout != null)
+        {
+            gridRef.LoadLayout(bandLayout.GridLayout);
+            gridLayoutApplied = true;
+            await InvokeAsync(StateHasChanged);
+        }
+    }
+
+    // --- Layout speichern / zurücksetzen ---
+    protected async Task SaveLayoutAsync()
+    {
+        if (string.IsNullOrWhiteSpace(layoutUser)) return;
+        CaptureColumnLayoutFromGrid();
+        await BandLayoutService.SaveBandLayoutAsync(LayoutType, LayoutKey, layoutUser, bandLayout);
+    }
+
+    protected async Task ResetLayoutAsync()
+    {
+        if (string.IsNullOrWhiteSpace(layoutUser)) return;
+        await BandLayoutService.ResetBandLayoutAsync(LayoutType, LayoutKey, layoutUser);
+        bandLayout = new BandLayout();
+        columnBandAssignments.Clear();
+        UpdateBandOptions();
+        foreach (var column in ColumnDefinitions)
+            column.Width = null;
+        columnLookup = ColumnDefinitions.ToDictionary(c => c.FieldName, StringComparer.OrdinalIgnoreCase);
+        _sizeMode = SizeMode.Medium;
+        gridRef?.LoadLayout(new GridPersistentLayout());
+        gridLayoutApplied = false;
+    }
+
+    private void CaptureColumnLayoutFromGrid()
+    {
+        if (gridRef == null) return;
+        var layout = gridRef.SaveLayout();
+        bandLayout.GridLayout = layout;
+        bandLayout.SizeMode = _sizeMode;
+        var orderedColumns = layout.Columns
+            .Where(c => !string.IsNullOrWhiteSpace(c.FieldName))
+            .OrderBy(c => c.VisibleIndex)
+            .ToList();
+        bandLayout.ColumnOrder = orderedColumns.Select(c => c.FieldName).ToList();
+        bandLayout.ColumnWidths = orderedColumns
+            .Where(c => !string.IsNullOrWhiteSpace(c.Width))
+            .ToDictionary(c => c.FieldName, c => c.Width, StringComparer.OrdinalIgnoreCase);
+    }
+
+    private void ApplyColumnLayoutFromStorage()
+    {
+        foreach (var column in ColumnDefinitions)
+        {
+            if (bandLayout.ColumnWidths.TryGetValue(column.FieldName, out var width) && !string.IsNullOrWhiteSpace(width))
+                column.Width = width;
+        }
+        columnLookup = ColumnDefinitions.ToDictionary(c => c.FieldName, StringComparer.OrdinalIgnoreCase);
+    }
+
+    // --- Band-Methoden ---
+    protected bool CanSaveBandLayout => !string.IsNullOrWhiteSpace(layoutUser);
+
+    protected virtual bool ShowCommandColumn => true;
+
+    protected void AddBand()
+    {
+        bandLayout.Bands.Add(new BandDefinition { Id = Guid.NewGuid().ToString("N"), Caption = "Band" });
+        UpdateBandOptions();
+    }
+
+    protected void RemoveBand(BandDefinition band)
+    {
+        bandLayout.Bands.Remove(band);
+        foreach (var key in columnBandAssignments.Where(p => p.Value == band.Id).Select(p => p.Key).ToList())
+            columnBandAssignments.Remove(key);
+        UpdateBandOptions();
+        SyncBandsFromAssignments();
+    }
+
+    protected void UpdateBandCaption(BandDefinition band, string value)
+    {
+        band.Caption = value;
+        UpdateBandOptions();
+    }
+
+    protected void UpdateColumnBand(string fieldName, string? bandId)
+    {
+        if (string.IsNullOrWhiteSpace(bandId))
+            columnBandAssignments.Remove(fieldName);
+        else
+            columnBandAssignments[fieldName] = bandId;
+        SyncBandsFromAssignments();
+    }
+
+    protected string GetColumnBand(string fieldName)
+        => columnBandAssignments.TryGetValue(fieldName, out var bandId) ? bandId : string.Empty;
+
+    protected void SyncBandsFromAssignments()
+    {
+        foreach (var band in bandLayout.Bands)
+        {
+            band.Columns = ColumnDefinitions
+                .Where(c => columnBandAssignments.TryGetValue(c.FieldName, out var id) && id == band.Id)
+                .Select(c => c.FieldName)
+                .ToList();
+        }
+        _ = InvokeAsync(StateHasChanged);
+    }
+
+    protected void UpdateBandOptions()
+    {
+        bandOptions = [new() { Id = string.Empty, Caption = "Ohne Band" }];
+        bandOptions.AddRange(bandLayout.Bands.Select(b => new BandOption { Id = b.Id, Caption = b.Caption }));
+    }
+
+    // --- SizeMode ---
+    protected string FormatSizeText(SizeMode size) => size switch
+    {
+        SizeMode.Small => "Klein",
+        SizeMode.Medium => "Mittel",
+        SizeMode.Large => "Groß",
+        _ => size.ToString()
+    };
+
+    protected void OnSizeChange(DropDownButtonItemClickEventArgs args)
+    {
+        _sizeMode = Enum.Parse<SizeMode>(args.ItemInfo.Id);
+    }
+
+    // --- RenderColumns / BuildDataColumn ---
+    protected RenderFragment RenderColumns() => builder =>
+    {
+        var seq = 0;
+        if (ShowCommandColumn)
+        {
+            builder.OpenComponent<DxGridCommandColumn>(seq++);
+            builder.AddAttribute(seq++, "Width", "120px");
+            builder.CloseComponent();
+        }
+
+        var grouped = bandLayout.Bands.SelectMany(b => b.Columns).ToHashSet(StringComparer.OrdinalIgnoreCase);
+        foreach (var column in ColumnDefinitions.Where(c => !grouped.Contains(c.FieldName)))
+            BuildDataColumn(builder, ref seq, column);
+
+        foreach (var band in bandLayout.Bands)
+        {
+            if (band.Columns.Count == 0) continue;
+            builder.OpenComponent<DxGridBandColumn>(seq++);
+            builder.AddAttribute(seq++, "Caption", band.Caption);
+            builder.AddAttribute(seq++, "Columns", (RenderFragment)(bandBuilder =>
+            {
+                var bandSeq = 0;
+                foreach (var columnName in band.Columns)
+                {
+                    if (columnLookup.TryGetValue(columnName, out var column))
+                        BuildDataColumn(bandBuilder, ref bandSeq, column);
+                }
+            }));
+            builder.CloseComponent();
+        }
+    };
+
+    protected void BuildDataColumn(RenderTreeBuilder builder, ref int seq, ColumnDefinition column)
+    {
+        builder.OpenComponent<DxGridDataColumn>(seq++);
+        builder.AddAttribute(seq++, "FieldName", column.FieldName);
+        builder.AddAttribute(seq++, "Caption", column.Caption);
+        if (!string.IsNullOrWhiteSpace(column.Width))
+            builder.AddAttribute(seq++, "Width", column.Width);
+        if (!string.IsNullOrWhiteSpace(column.DisplayFormat))
+            builder.AddAttribute(seq++, "DisplayFormat", column.DisplayFormat);
+        if (column.ReadOnly)
+            builder.AddAttribute(seq++, "ReadOnly", true);
+        builder.CloseComponent();
+    }
+
+    protected void SetEditContext(EditContext context)
+    {
+        if (editContext == context) return;
+        if (editContext != null)
+            editContext.OnFieldChanged -= OnEditFieldChanged;
+        editContext = context;
+        validationMessageStore = new ValidationMessageStore(editContext);
+        editContext.OnFieldChanged += OnEditFieldChanged;
+    }
+
+    protected virtual void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
+    {
+        validationMessageStore?.Clear();
+        editContext?.NotifyValidationStateChanged();
+    }
+
+    protected void SetPopupHeaderText(bool isNew) => popupHeaderText = isNew ? "Neu" : "Edit";
+
+    protected async Task EditFocusedRow()
+        => await gridRef!.StartEditRowAsync(_focusedVisibleIndex);
+
+    protected Task DeleteFocusedRow()
+    {
+        gridRef!.ShowRowDeleteConfirmation(_focusedVisibleIndex);
+        return Task.CompletedTask;
+    }
+
+    protected async Task SaveLayoutWithFeedbackAsync()
+    {
+        try
+        {
+            await SaveLayoutAsync();
+            infoMessage = "Layout gespeichert.";
+            errorMessage = null;
+        }
+        catch (Exception ex)
+        {
+            errorMessage = $"Layout konnte nicht gespeichert werden: {ex.Message}";
+        }
+    }
+
+    protected async Task ResetLayoutWithFeedbackAsync()
+    {
+        await ResetLayoutAsync();
+        infoMessage = "Layout zurückgesetzt.";
+        errorMessage = null;
+    }
+
+}
--- a/DbFirst.BlazorWebApp/Components/CatalogsGrid.razor
+++ b/DbFirst.BlazorWebApp/Components/CatalogsGrid.razor
@@ -1,54 +1,5 @@
-@using System.Text.Json
-@using Microsoft.AspNetCore.Components
-@using Microsoft.AspNetCore.Components.Rendering
-@using Microsoft.AspNetCore.Components.Forms
-@using DevExpress.Blazor
-@using DevExpress.Data.Filtering
-@inject CatalogApiClient Api
-@inject LayoutApiClient LayoutApi
-@inject IJSRuntime JsRuntime
-
-<style>
-    .action-panel { margin-bottom: 16px; }
-    .grid-section { margin-top: 12px; }
-    .catalog-edit-popup {
-        min-width: 720px;
-    }
-    .band-editor {
-        display: grid;
-        gap: 12px;
-        margin-bottom: 16px;
-    }
-    .band-controls {
-        display: flex;
-        flex-wrap: wrap;
-        gap: 8px;
-        align-items: center;
-    }
-    .band-row {
-        display: flex;
-        gap: 8px;
-        align-items: center;
-    }
-    .band-columns {
-        max-width: 720px;
-    }
-    .filter-row-cell {
-        display: flex;
-        align-items: center;
-        gap: 4px;
-        flex-wrap: wrap;
-    }
-    .filter-operator {
-        width: 52px;
-        min-width: 52px;
-        flex: 0 0 52px;
-    }
-    .filter-value {
-        min-width: 140px;
-        flex: 1 1 140px;
-    }
-</style>
+@inherits BandGridBase<CatalogReadDto>
+@inject ICatalogApiClient Api

@if (!string.IsNullOrWhiteSpace(errorMessage))
 {
@@ -59,9 +10,13 @@ else if (!string.IsNullOrWhiteSpace(infoMessage))
    <div class="alert alert-success" role="alert">@infoMessage</div>
 }

-@if (isLoading)
+@if (!hasLoaded || isLoading)
 {
-    <p><em>Lade Daten...</em></p>
+    <div class="loading-container">
+        <div class="spinner-border text-primary" role="status">
+            <span class="visually-hidden">Lade...</span>
+        </div>
+    </div>
 }
 else if (items.Count == 0)
 {
@@ -69,44 +24,28 @@ else if (items.Count == 0)
 }
 else
 {
-    <div class="band-editor">
-        <div class="band-controls">
-            <DxButton Text="Band hinzufügen" Click="AddBand" />
-            <DxButton Text="Layout speichern" Click="SaveLayoutAsync" Enabled="@CanSaveBandLayout" />
-            <DxButton Text="Band-Layout zurücksetzen" Click="ResetBandLayoutAsync" />
-        </div>
-        @foreach (var band in bandLayout.Bands)
-        {
-            <div class="band-row">
-                <DxTextBox Text="@band.Caption" TextChanged="@(value => UpdateBandCaption(band, value))" />
-                <DxButton Text="Entfernen" Click="@(() => RemoveBand(band))" />
-            </div>
-        }
-        <DxFormLayout CssClass="band-columns" ColCount="2">
-            @foreach (var column in columnDefinitions)
-            {
-                <DxFormLayoutItem Caption="@column.Caption">
-                    <DxComboBox Data="@bandOptions"
-                                TData="BandOption"
-                                TValue="string"
-                                TextFieldName="Caption"
-                                ValueFieldName="Id"
-                                Value="@GetColumnBand(column.FieldName)"
-                                ValueChanged="@(value => UpdateColumnBand(column.FieldName, value))"
-                                Width="100%" />
-                </DxFormLayoutItem>
-            }
-        </DxFormLayout>
-    </div>
+    <BandEditor Bands="@bandLayout.Bands"
+                BandOptions="@bandOptions"
+                Columns="@ColumnDefinitions"
+                GetColumnBand="GetColumnBand"
+                CanSave="@CanSaveBandLayout"
+                OnAddBand="AddBand"
+                OnSaveLayout="SaveLayoutWithFeedbackAsync"
+                OnResetLayout="ResetLayoutWithFeedbackAsync"
+                OnRemoveBand="RemoveBand"
+                OnBandCaptionChanged="@(args => UpdateBandCaption(args.Band, args.Value))"
+                OnColumnBandChanged="@(args => UpdateColumnBand(args.FieldName, args.BandId))" />

    <div class="grid-section">
        <DxGrid Data="@items"
+                ColumnChooserButtonDisplayMode="GridColumnChooserButtonDisplayMode.Always"
                TItem="CatalogReadDto"
                KeyFieldName="@nameof(CatalogReadDto.Guid)"
+                SizeMode="@_sizeMode"
                ShowGroupPanel="true"
                ShowGroupedColumns="true"
                AllowGroup="true"
-                ShowFilterRow="true"
+                FilterMenuButtonDisplayMode="GridFilterMenuButtonDisplayMode.Always"
                AllowColumnResize="true"
                ColumnResizeMode="GridColumnResizeMode.ColumnsContainer"
                AllowColumnReorder="true"
@@ -118,12 +57,68 @@ else
                CustomizeEditModel="OnCustomizeEditModel"
                EditModelSaving="OnEditModelSaving"
                DataItemDeleting="OnDataItemDeleting"
+                FocusedRowEnabled="true"
+                @bind-FocusedRowKey="focusedRowKey"
+                RowClick="@(args => _focusedVisibleIndex = args.VisibleIndex)"
                @ref="gridRef">
+            <ToolbarTemplate>
+                <DxToolbar>
+                    <DxToolbarItem Alignment="ToolbarItemAlignment.Left">
+                        <Template Context="_">
+                            <DxButton IconCssClass="bi bi-plus-lg"
+                                      RenderStyle="ButtonRenderStyle.Secondary"
+                                      RenderStyleMode="ButtonRenderStyleMode.Text"
+                                      Click="@(() => gridRef!.StartEditNewRowAsync())" />
+                        </Template>
+                    </DxToolbarItem>
+                    <DxToolbarItem Alignment="ToolbarItemAlignment.Left">
+                        <Template Context="_">
+                            <DxButton IconCssClass="bi bi-pencil"
+                                      RenderStyle="ButtonRenderStyle.Secondary"
+                                      RenderStyleMode="ButtonRenderStyleMode.Text"
+                                      Click="EditFocusedRow" />
+                        </Template>
+                    </DxToolbarItem>
+                    <DxToolbarItem Alignment="ToolbarItemAlignment.Left">
+                        <Template Context="_">
+                            <DxButton IconCssClass="bi bi-trash"
+                                      RenderStyle="ButtonRenderStyle.Secondary"
+                                      RenderStyleMode="ButtonRenderStyleMode.Text"
+                                      Click="DeleteFocusedRow" />
+                        </Template>
+                    </DxToolbarItem>
+                    <DxToolbarItem Alignment="ToolbarItemAlignment.Right">
+                        <Template Context="_">
+                            <DxButton Text="Spalten"
+                                      RenderStyle="ButtonRenderStyle.Secondary"
+                                      RenderStyleMode="ButtonRenderStyleMode.Text"
+                                      Click="@(() => gridRef!.ShowColumnChooser())" />
+                        </Template>
+                    </DxToolbarItem>
+                    <DxToolbarItem Alignment="ToolbarItemAlignment.Right">
+                        <Template Context="_">
+                            <DxDropDownButton Text="@FormatSizeText(_sizeMode)"
+                                              RenderStyle="ButtonRenderStyle.Secondary"
+                                              RenderStyleMode="ButtonRenderStyleMode.Text"
+                                              ItemClick="OnSizeChange">
+                                <Items>
+                                    @foreach (var size in _sizeModes)
+                                    {
+                                        <DxDropDownButtonItem Text="@FormatSizeText(size)" Id="@size.ToString()" />
+                                    }
+                                </Items>
+                            </DxDropDownButton>
+                        </Template>
+                    </DxToolbarItem>
+                </DxToolbar>
+            </ToolbarTemplate>
            <Columns>
                @RenderColumns()
            </Columns>
            <EditFormTemplate Context="editFormContext">
-                @{ SetEditContext(editFormContext.EditContext); var editModel = (CatalogEditModel)editFormContext.EditModel; SetPopupHeaderText(editModel.IsNew); }
+                @{
+                    SetEditContext(editFormContext.EditContext); var editModel = (CatalogEditModel)editFormContext.EditModel; SetPopupHeaderText(editModel.IsNew);
+                }
                <DxFormLayout ColCount="2">
                    <DxFormLayoutItem Caption="Titel">
                        <DxTextBox @bind-Text="editModel.CatTitle" Width="100%" />
@@ -154,36 +149,21 @@ else

@code {
    private List<CatalogReadDto> items = new();
-    private bool isLoading;
-    private string? errorMessage;
-    private string? infoMessage;
-    private EditContext? editContext;
-    private ValidationMessageStore? validationMessageStore;
-    private IGrid? gridRef;
-    private string popupHeaderText = "Edit";
-    private DateTime? addedWhenFilterValue;
-    private string addedWhenFilterOperator = "=";
-    private DateTime? changedWhenFilterValue;
-    private string changedWhenFilterOperator = "=";
-    private const string LayoutType = "GRID_BANDS";
-    private const string LayoutKey = "CatalogsGrid";
-    private const string LayoutUserStorageKey = "layoutUser";
-    private string? layoutUser;
-    private BandLayout bandLayout = new();
-    private Dictionary<string, string> columnBandAssignments = new();
-    private List<BandOption> bandOptions = new();
-    private Dictionary<string, ColumnDefinition> columnLookup = new();
-    private readonly JsonSerializerOptions jsonOptions = new(JsonSerializerDefaults.Web);
-    private List<ColumnDefinition> columnDefinitions = new()
-    {
-        new() { FieldName = nameof(CatalogReadDto.Guid), Caption = "Id", Width = "140px", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.CatTitle), Caption = "Titel", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.CatString), Caption = "String", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.AddedWho), Caption = "Angelegt von", ReadOnly = true, FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.AddedWhen), Caption = "Angelegt am", ReadOnly = true, FilterType = ColumnFilterType.Date },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWho), Caption = "Geändert von", ReadOnly = true, FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWhen), Caption = "Geändert am", ReadOnly = true, FilterType = ColumnFilterType.Date }
-    };
+    private int? focusedRowKey;
+
+    protected override string LayoutKey => "CatalogsGrid";
+    protected override bool ShowCommandColumn => false;
+
+    protected override List<ColumnDefinition> ColumnDefinitions { get; } = new()
+{
+    new() { FieldName = nameof(CatalogReadDto.Guid),       Caption = "Id",          Width = "140px", FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.CatTitle),   Caption = "Titel",                        FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.CatString),  Caption = "String",                       FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.AddedWho),   Caption = "Angelegt von", ReadOnly = true, FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.AddedWhen),  Caption = "Angelegt am",  ReadOnly = true, FilterType = ColumnFilterType.Date },
+    new() { FieldName = nameof(CatalogReadDto.ChangedWho), Caption = "Geändert von", ReadOnly = true, FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.ChangedWhen),Caption = "Geändert am",  ReadOnly = true, FilterType = ColumnFilterType.Date }
+};

    private readonly List<ProcedureOption> procedureOptions = new()
    {
@@ -191,59 +171,40 @@ else
        new() { Value = 1, Text = "PRTBMY_CATALOG_SAVE" }
    };

-    private readonly List<FilterOperatorOption> filterOperators = new()
-    {
-        new() { Value = "=", Text = "=" },
-        new() { Value = "<", Text = "<" },
-        new() { Value = ">", Text = ">" },
-        new() { Value = "<=", Text = "<=" },
-        new() { Value = ">=", Text = ">=" }
-    };
-
-    private bool CanSaveBandLayout => !string.IsNullOrWhiteSpace(layoutUser);
-    private bool gridLayoutApplied;
-
    protected override async Task OnInitializedAsync()
    {
-        columnLookup = columnDefinitions.ToDictionary(column => column.FieldName, StringComparer.OrdinalIgnoreCase);
-        await EnsureLayoutUserAsync();
-        await LoadBandLayoutAsync();
+        await InitializeBandLayoutAsync();
        await LoadCatalogs();
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
-        if (!gridLayoutApplied && gridRef != null && bandLayout.GridLayout != null)
+        await ApplyGridLayoutAfterRenderAsync();
+    }
+
+    private async Task LoadCatalogs()
+    {
+        isLoading = true;
+        errorMessage = null;
+        try
        {
-            gridRef.LoadLayout(bandLayout.GridLayout);
-            gridLayoutApplied = true;
-            await InvokeAsync(StateHasChanged);
+            items = await Api.GetAllAsync();
+        }
+        catch (Exception ex)
+        {
+            errorMessage = $"Kataloge konnten nicht geladen werden: {ex.Message}";
+        }
+        finally
+        {
+            isLoading = false;
+            hasLoaded = true;
+            StateHasChanged();
        }
    }

-    private void SetEditContext(EditContext context)
+    protected override void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
    {
-        if (editContext == context)
-        {
-            return;
-        }
-
-        if (editContext != null)
-        {
-            editContext.OnFieldChanged -= OnEditFieldChanged;
-        }
-
-        editContext = context;
-        validationMessageStore = new ValidationMessageStore(editContext);
-        editContext.OnFieldChanged += OnEditFieldChanged;
-    }
-
-    private void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
-    {
-        if (validationMessageStore == null || editContext == null)
-        {
-            return;
-        }
+        if (validationMessageStore == null || editContext == null) return;

        if (e.FieldIdentifier.FieldName == nameof(CatalogEditModel.UpdateProcedure))
        {
@@ -254,17 +215,11 @@ else

        if (e.FieldIdentifier.FieldName == nameof(CatalogEditModel.CatTitle))
        {
-            var field = new FieldIdentifier(editContext.Model, nameof(CatalogEditModel.CatTitle));
-            validationMessageStore.Clear(field);
+            validationMessageStore.Clear(new FieldIdentifier(editContext.Model, nameof(CatalogEditModel.CatTitle)));
            editContext.NotifyValidationStateChanged();
        }
    }

-    private void SetPopupHeaderText(bool isNew)
-    {
-        popupHeaderText = isNew ? "Neu" : "Edit";
-    }
-
    private void OnCustomizeEditModel(GridCustomizeEditModelEventArgs e)
    {
        popupHeaderText = e.IsNew ? "Neu" : "Edit";
@@ -286,30 +241,10 @@ else
        };
    }

-    private async Task LoadCatalogs()
-    {
-        isLoading = true;
-        errorMessage = null;
-        try
-        {
-            items = await Api.GetAllAsync();
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Kataloge konnten nicht geladen werden: {ex.Message}";
-        }
-        finally
-        {
-            isLoading = false;
-            StateHasChanged();
-        }
-    }
-
    private async Task OnEditModelSaving(GridEditModelSavingEventArgs e)
    {
        errorMessage = null;
        infoMessage = null;
-
        validationMessageStore?.Clear();
        editContext?.NotifyValidationStateChanged();

@@ -324,7 +259,7 @@ else
        {
            CatTitle = editModel.CatTitle,
            CatString = editModel.CatString,
-            UpdateProcedure = editModel.UpdateProcedure
+            UpdateProcedure = (CatalogUpdateProcedure)editModel.UpdateProcedure
        };

        try
@@ -335,19 +270,14 @@ else
                if (!created.Success || created.Value == null)
                {
                    if (!string.IsNullOrWhiteSpace(created.Error))
-                    {
                        AddValidationError(editModel, nameof(CatalogEditModel.CatTitle), created.Error);
-                    }
                    else
-                    {
                        errorMessage = "Anlegen fehlgeschlagen.";
-                    }
-
                    e.Cancel = true;
                    return;
                }
-
                infoMessage = "Katalog angelegt.";
+                focusedRowKey = created.Value.Guid;
            }
            else
            {
@@ -358,8 +288,8 @@ else
                    e.Cancel = true;
                    return;
                }
-
                infoMessage = "Katalog aktualisiert.";
+                focusedRowKey = editModel.Guid;
            }

            await LoadCatalogs();
@@ -373,30 +303,20 @@ else

    private void AddValidationError(CatalogEditModel editModel, string fieldName, string message)
    {
-        if (editContext == null || validationMessageStore == null)
-        {
-            return;
-        }
-
-        var field = new FieldIdentifier(editModel, fieldName);
-        validationMessageStore.Add(field, message);
+        if (editContext == null || validationMessageStore == null) return;
+        validationMessageStore.Add(new FieldIdentifier(editModel, fieldName), message);
        editContext.NotifyValidationStateChanged();
    }

    private bool ValidateEditModel(CatalogEditModel editModel, bool isNew)
    {
-        if (isNew)
-        {
-            return true;
-        }
-
+        if (isNew) return true;
        if (editModel.UpdateProcedure == 0 &&
            !string.Equals(editModel.CatTitle, editModel.OriginalCatTitle, StringComparison.OrdinalIgnoreCase))
        {
            AddValidationError(editModel, nameof(CatalogEditModel.CatTitle), "Titel kann nicht geändert werden.");
            return false;
        }
-
        return true;
    }

@@ -404,9 +324,7 @@ else
    {
        errorMessage = null;
        infoMessage = null;
-
        var item = (CatalogReadDto)e.DataItem;
-
        try
        {
            var deleted = await Api.DeleteAsync(item.Guid);
@@ -416,7 +334,6 @@ else
                e.Cancel = true;
                return;
            }
-
            infoMessage = "Katalog gelöscht.";
            await LoadCatalogs();
        }
@@ -427,411 +344,6 @@ else
        }
    }

-    private async Task EnsureLayoutUserAsync()
-    {
-        layoutUser = await JsRuntime.InvokeAsync<string?>("localStorage.getItem", LayoutUserStorageKey);
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            layoutUser = Guid.NewGuid().ToString("N");
-            await JsRuntime.InvokeVoidAsync("localStorage.setItem", LayoutUserStorageKey, layoutUser);
-        }
-    }
-
-    private async Task SaveLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            return;
-        }
-
-        try
-        {
-            CaptureColumnLayoutFromGrid();
-
-            var layoutData = JsonSerializer.Serialize(bandLayout, jsonOptions);
-            await LayoutApi.UpsertAsync(new LayoutDto
-            {
-                LayoutType = LayoutType,
-                LayoutKey = LayoutKey,
-                UserName = layoutUser,
-                LayoutData = layoutData
-            });
-            infoMessage = "Layout gespeichert.";
-            errorMessage = null;
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Layout konnte nicht gespeichert werden: {ex.Message}";
-        }
-    }
-
-    private void CaptureColumnLayoutFromGrid()
-    {
-        if (gridRef == null)
-        {
-            return;
-        }
-
-        var layout = gridRef.SaveLayout();
-        bandLayout.GridLayout = layout;
-
-        var orderedColumns = layout.Columns
-            .Where(column => !string.IsNullOrWhiteSpace(column.FieldName))
-            .OrderBy(column => column.VisibleIndex)
-            .ToList();
-
-        bandLayout.ColumnOrder = orderedColumns
-            .Select(column => column.FieldName)
-            .ToList();
-
-        bandLayout.ColumnWidths = orderedColumns
-            .Where(column => !string.IsNullOrWhiteSpace(column.Width))
-            .ToDictionary(column => column.FieldName, column => column.Width, StringComparer.OrdinalIgnoreCase);
-    }
-
-    private async Task LoadBandLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            bandLayout = new BandLayout();
-            UpdateBandOptions();
-            return;
-        }
-
-        var stored = await LayoutApi.GetAsync(LayoutType, LayoutKey, layoutUser);
-        if (stored != null && !string.IsNullOrWhiteSpace(stored.LayoutData))
-        {
-            var parsed = JsonSerializer.Deserialize<BandLayout>(stored.LayoutData, jsonOptions);
-            bandLayout = NormalizeBandLayout(parsed);
-        }
-        else
-        {
-            bandLayout = new BandLayout();
-        }
-
-        columnBandAssignments = BuildAssignmentsFromLayout(bandLayout);
-        ApplyColumnLayoutFromStorage();
-        UpdateBandOptions();
-    }
-
-    private async Task ResetBandLayoutAsync()
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-        {
-            return;
-        }
-
-        await LayoutApi.DeleteAsync(LayoutType, LayoutKey, layoutUser);
-        bandLayout = new BandLayout();
-        columnBandAssignments.Clear();
-        UpdateBandOptions();
-        infoMessage = "Band-Layout zurückgesetzt.";
-    }
-
-    private void ApplyColumnLayoutFromStorage()
-    {
-        foreach (var column in columnDefinitions)
-        {
-            if (bandLayout.ColumnWidths.TryGetValue(column.FieldName, out var width) && !string.IsNullOrWhiteSpace(width))
-            {
-                column.Width = width;
-            }
-        }
-
-        columnLookup = columnDefinitions.ToDictionary(column => column.FieldName, StringComparer.OrdinalIgnoreCase);
-    }
-
-    private void AddBand()
-    {
-        bandLayout.Bands.Add(new BandDefinition
-        {
-            Id = Guid.NewGuid().ToString("N"),
-            Caption = "Band"
-        });
-        UpdateBandOptions();
-    }
-
-    private void RemoveBand(BandDefinition band)
-    {
-        bandLayout.Bands.Remove(band);
-        var removedColumns = columnBandAssignments.Where(pair => pair.Value == band.Id)
-            .Select(pair => pair.Key)
-            .ToList();
-        foreach (var column in removedColumns)
-        {
-            columnBandAssignments.Remove(column);
-        }
-        UpdateBandOptions();
-        SyncBandsFromAssignments();
-    }
-
-    private void UpdateBandCaption(BandDefinition band, string value)
-    {
-        band.Caption = value;
-        UpdateBandOptions();
-    }
-
-    private void UpdateColumnBand(string fieldName, string? bandId)
-    {
-        if (string.IsNullOrWhiteSpace(bandId))
-        {
-            columnBandAssignments.Remove(fieldName);
-        }
-        else
-        {
-            columnBandAssignments[fieldName] = bandId;
-        }
-
-        SyncBandsFromAssignments();
-    }
-
-    private string GetColumnBand(string fieldName)
-    {
-        return columnBandAssignments.TryGetValue(fieldName, out var bandId) ? bandId : string.Empty;
-    }
-
-    private void SyncBandsFromAssignments()
-    {
-        foreach (var band in bandLayout.Bands)
-        {
-            band.Columns = columnDefinitions
-                .Where(column => columnBandAssignments.TryGetValue(column.FieldName, out var bandId) && bandId == band.Id)
-                .Select(column => column.FieldName)
-                .ToList();
-        }
-
-        StateHasChanged();
-    }
-
-    private void UpdateBandOptions()
-    {
-        bandOptions = new List<BandOption> { new() { Id = string.Empty, Caption = "Ohne Band" } };
-        bandOptions.AddRange(bandLayout.Bands.Select(band => new BandOption { Id = band.Id, Caption = band.Caption }));
-    }
-
-    private BandLayout NormalizeBandLayout(BandLayout? layout)
-    {
-        layout ??= new BandLayout();
-        layout.Bands ??= new List<BandDefinition>();
-        layout.ColumnOrder ??= new List<string>();
-        layout.ColumnWidths ??= new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
-        foreach (var band in layout.Bands)
-        {
-            if (string.IsNullOrWhiteSpace(band.Id))
-            {
-                band.Id = Guid.NewGuid().ToString("N");
-            }
-
-            if (string.IsNullOrWhiteSpace(band.Caption))
-            {
-                band.Caption = "Band";
-            }
-
-            band.Columns = band.Columns?.Where(columnLookup.ContainsKey).ToList() ?? new List<string>();
-        }
-
-        return layout;
-    }
-
-    private Dictionary<string, string> BuildAssignmentsFromLayout(BandLayout layout)
-    {
-        var assignments = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
-        foreach (var band in layout.Bands)
-        {
-            foreach (var column in band.Columns)
-            {
-                assignments[column] = band.Id;
-            }
-        }
-
-        return assignments;
-    }
-
-    private RenderFragment RenderColumns() => builder =>
-    {
-        var seq = 0;
-        builder.OpenComponent<DxGridCommandColumn>(seq++);
-        builder.AddAttribute(seq++, "Width", "120px");
-        builder.CloseComponent();
-
-        var grouped = bandLayout.Bands.SelectMany(band => band.Columns).ToHashSet(StringComparer.OrdinalIgnoreCase);
-        foreach (var column in columnDefinitions.Where(column => !grouped.Contains(column.FieldName)))
-        {
-            BuildDataColumn(builder, ref seq, column);
-        }
-
-        foreach (var band in bandLayout.Bands)
-        {
-            if (band.Columns.Count == 0)
-            {
-                continue;
-            }
-
-            builder.OpenComponent<DxGridBandColumn>(seq++);
-            builder.AddAttribute(seq++, "Caption", band.Caption);
-            builder.AddAttribute(seq++, "Columns", (RenderFragment)(bandBuilder =>
-            {
-                var bandSeq = 0;
-                foreach (var columnName in band.Columns)
-                {
-                    if (columnLookup.TryGetValue(columnName, out var column))
-                    {
-                        BuildDataColumn(bandBuilder, ref bandSeq, column);
-                    }
-                }
-            }));
-            builder.CloseComponent();
-        }
-    };
-
-    private void BuildDataColumn(RenderTreeBuilder builder, ref int seq, ColumnDefinition column)
-    {
-        builder.OpenComponent<DxGridDataColumn>(seq++);
-        builder.AddAttribute(seq++, "FieldName", column.FieldName);
-        builder.AddAttribute(seq++, "Caption", column.Caption);
-        if (!string.IsNullOrWhiteSpace(column.Width))
-        {
-            builder.AddAttribute(seq++, "Width", column.Width);
-        }
-
-        if (!string.IsNullOrWhiteSpace(column.DisplayFormat))
-        {
-            builder.AddAttribute(seq++, "DisplayFormat", column.DisplayFormat);
-        }
-
-        if (column.ReadOnly)
-        {
-            builder.AddAttribute(seq++, "ReadOnly", true);
-        }
-
-        if (string.Equals(column.FieldName, nameof(CatalogReadDto.AddedWhen), StringComparison.OrdinalIgnoreCase))
-        {
-            builder.AddAttribute(seq++, "FilterRowCellTemplate", BuildAddedWhenFilterTemplate());
-        }
-        else if (string.Equals(column.FieldName, nameof(CatalogReadDto.ChangedWhen), StringComparison.OrdinalIgnoreCase))
-        {
-            builder.AddAttribute(seq++, "FilterRowCellTemplate", BuildChangedWhenFilterTemplate());
-        }
-
-        builder.CloseComponent();
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildAddedWhenFilterTemplate()
-    {
-        return BuildDateFilterTemplate(
-            () => addedWhenFilterValue,
-            value => addedWhenFilterValue = value,
-            () => addedWhenFilterOperator,
-            value => addedWhenFilterOperator = value);
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildChangedWhenFilterTemplate()
-    {
-        return BuildDateFilterTemplate(
-            () => changedWhenFilterValue,
-            value => changedWhenFilterValue = value,
-            () => changedWhenFilterOperator,
-            value => changedWhenFilterOperator = value);
-    }
-
-    private RenderFragment<GridDataColumnFilterRowCellTemplateContext> BuildDateFilterTemplate(
-        Func<DateTime?> getValue,
-        Action<DateTime?> setValue,
-        Func<string> getOperator,
-        Action<string> setOperator)
-    {
-        return context => builder =>
-        {
-            var seq = 0;
-            builder.OpenElement(seq++, "div");
-            builder.AddAttribute(seq++, "class", "filter-row-cell");
-
-            builder.OpenComponent<DxComboBox<FilterOperatorOption, string>>(seq++);
-            builder.AddAttribute(seq++, "Data", filterOperators);
-            builder.AddAttribute(seq++, "TextFieldName", "Text");
-            builder.AddAttribute(seq++, "ValueFieldName", "Value");
-            builder.AddAttribute(seq++, "Value", getOperator());
-            builder.AddAttribute(seq++, "ValueChanged", EventCallback.Factory.Create<string>(this, value =>
-            {
-                setOperator(value);
-                UpdateFilterCriteria(context, value, getValue());
-            }));
-            builder.AddAttribute(seq++, "CssClass", "filter-operator");
-            builder.CloseComponent();
-
-            builder.OpenComponent<DxDateEdit<DateTime?>>(seq++);
-            builder.AddAttribute(seq++, "Date", getValue());
-            builder.AddAttribute(seq++, "DateChanged", EventCallback.Factory.Create<DateTime?>(this, value =>
-            {
-                setValue(value);
-                UpdateFilterCriteria(context, getOperator(), value);
-            }));
-            builder.AddAttribute(seq++, "ClearButtonDisplayMode", DataEditorClearButtonDisplayMode.Auto);
-            builder.AddAttribute(seq++, "CssClass", "filter-value");
-            builder.CloseComponent();
-
-            builder.CloseElement();
-        };
-    }
-
-    private void UpdateFilterCriteria(GridDataColumnFilterRowCellTemplateContext context, string op, DateTime? value)
-    {
-        if (!value.HasValue)
-        {
-            context.FilterCriteria = null;
-            return;
-        }
-
-        var prop = new OperandProperty(context.DataColumn.FieldName);
-        var date = value.Value.Date;
-        context.FilterCriteria = op switch
-        {
-            "=" => new GroupOperator(GroupOperatorType.And, prop >= date, prop < date.AddDays(1)),
-            "<" => prop < date,
-            "<=" => prop < date.AddDays(1),
-            ">" => prop >= date.AddDays(1),
-            ">=" => prop >= date,
-            _ => prop == date
-        };
-    }
-
-    private sealed class BandLayout
-    {
-        public List<BandDefinition> Bands { get; set; } = new();
-        public List<string> ColumnOrder { get; set; } = new();
-        public Dictionary<string, string?> ColumnWidths { get; set; } = new(StringComparer.OrdinalIgnoreCase);
-        public GridPersistentLayout? GridLayout { get; set; }
-    }
-
-    private sealed class BandDefinition
-    {
-        public string Id { get; set; } = string.Empty;
-        public string Caption { get; set; } = string.Empty;
-        public List<string> Columns { get; set; } = new();
-    }
-
-    private sealed class BandOption
-    {
-        public string Id { get; set; } = string.Empty;
-        public string Caption { get; set; } = string.Empty;
-    }
-
-    private sealed class ColumnDefinition
-    {
-        public string FieldName { get; init; } = string.Empty;
-        public string Caption { get; init; } = string.Empty;
-        public string? Width { get; set; }
-        public string? DisplayFormat { get; init; }
-        public bool ReadOnly { get; init; }
-        public ColumnFilterType FilterType { get; init; }
-    }
-
-    private enum ColumnFilterType
-    {
-        Text,
-        Date
-    }
-
    private sealed class CatalogEditModel
    {
        public int Guid { get; set; }
@@ -847,10 +359,4 @@ else
        public int Value { get; set; }
        public string Text { get; set; } = string.Empty;
    }
-
-    private sealed class FilterOperatorOption
-    {
-        public string Value { get; set; } = string.Empty;
-        public string Text { get; set; } = string.Empty;
-    }
-}
+}
--- a/DbFirst.BlazorWebApp/Components/CatalogsGrid.razor.css
+++ b/DbFirst.BlazorWebApp/Components/CatalogsGrid.razor.css
@@ -0,0 +1,3 @@
+.catalog-edit-popup {
+    min-width: 720px;
+}
--- a/DbFirst.BlazorWebApp/Components/Layout/MainLayout.razor
+++ b/DbFirst.BlazorWebApp/Components/Layout/MainLayout.razor
@@ -1,12 +1,23 @@
@inherits LayoutComponentBase
+@implements IDisposable
+@inject ThemeState ThemeState
+@inject IJSRuntime JS

-<div class="page">
+<div class="page @(ThemeState.IsDarkMode ? "app-dark" : "app-light") @(ThemeState.IsNativeDarkTheme ? "native-dark" : "")">
    <div class="sidebar">
        <NavMenu />
    </div>

    <main>
        <div class="top-row px-4">
+            <DxComboBox Data="@ThemeState.AvailableThemes"
+                        Value="@ThemeState.CurrentThemeName"
+                        ValueChanged="@((string t) => ThemeState.SetTheme(t))"
+                        style="width: 130px;" />
+            <span style="margin-left: 12px;">
+                <DxButton Text="@(ThemeState.IsDarkMode ? "Dark Mode aus" : "Dark Mode an")"
+                          Click="ToggleTheme" />
+            </span>
            <a href="https://learn.microsoft.com/aspnet/core/" target="_blank">About</a>
        </div>

@@ -21,3 +32,54 @@
    <a href="" class="reload">Reload</a>
    <a class="dismiss">🗙</a>
 </div>
+
+@code {
+    private bool _isInteractive;
+
+    protected override void OnInitialized()
+    {
+        ThemeState.OnChange += OnThemeChanged;
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            _isInteractive = true;
+        }
+        await ApplyDxDarkOverrideAsync();
+    }
+
+    private async void OnThemeChanged()
+    {
+        StateHasChanged();
+        if (_isInteractive)
+        {
+            await ApplyDxDarkOverrideAsync();
+        }
+    }
+
+    private async Task ApplyDxDarkOverrideAsync()
+    {
+        if (!_isInteractive) return;
+        try
+        {
+            bool needsOverride = ThemeState.IsDarkMode && !ThemeState.IsNativeDarkTheme;
+            await JS.InvokeVoidAsync("setDxDarkOverride", needsOverride);
+        }
+        catch (JSException)
+        {
+            // JS-Funktion noch nicht verfügbar – kein Circuit-Crash
+        }
+    }
+
+    private void ToggleTheme()
+    {
+        ThemeState.SetDarkMode(!ThemeState.IsDarkMode);
+    }
+
+    public void Dispose()
+    {
+        ThemeState.OnChange -= OnThemeChanged;
+    }
+}
--- a/DbFirst.BlazorWebApp/Components/Layout/MainLayout.razor.css
+++ b/DbFirst.BlazorWebApp/Components/Layout/MainLayout.razor.css
@@ -4,12 +4,27 @@
    flex-direction: column;
 }

+.page.app-dark {
+    background-color: #1b1b1b;
+    color: #f1f1f1;
+}
+
 main {
    flex: 1;
 }

+.page.app-dark main {
+    background-color: #1b1b1b;
+}
+
 .sidebar {
-    background-image: linear-gradient(180deg, rgb(5, 39, 103) 0%, #3a0647 70%);
+    background-color: var(--dx-color-surface-container, #f4f4f4);
+    border-right: 1px solid var(--dx-color-outline-variant, #e0e0e0);
+}
+
+.page.app-dark .sidebar {
+    background-color: var(--dx-color-surface-container, #1e1e1e);
+    border-right-color: var(--dx-color-outline-variant, #333);
 }

 .top-row {
@@ -21,6 +36,11 @@ main {
    align-items: center;
 }

+.page.app-dark .top-row {
+    background-color: #222;
+    border-bottom-color: #3d3d3d;
+}
+
    .top-row ::deep a, .top-row ::deep .btn-link {
        white-space: nowrap;
        margin-left: 1.5rem;
--- a/DbFirst.BlazorWebApp/Components/Layout/NavMenu.razor
+++ b/DbFirst.BlazorWebApp/Components/Layout/NavMenu.razor
@@ -1,36 +1,24 @@
-<div class="top-row ps-3 navbar navbar-dark">
-    <div class="container-fluid">
-        <a class="navbar-brand" href="">DbFirst.BlazorWebApp</a>
-    </div>
+<div class="nav-brand-row">
+    <a class="nav-brand-link" href="">DbFirst</a>
+    <button class="nav-toggle-btn" @onclick="ToggleMenu" title="Navigation menu">&#9776;</button>
 </div>

-<input type="checkbox" title="Navigation menu" class="navbar-toggler" />
-
-<div class="nav-scrollable" onclick="document.querySelector('.navbar-toggler').click()">
-    <nav class="flex-column">
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="" Match="NavLinkMatch.All">
-                <span class="bi bi-house-door-fill-nav-menu" aria-hidden="true"></span> Home
-            </NavLink>
-        </div>
-
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="catalogs">
-                <span class="bi bi-collection-nav-menu" aria-hidden="true"></span> Catalogs
-            </NavLink>
-        </div>
-
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="dashboards">
-                <span class="bi bi-speedometer-nav-menu" aria-hidden="true"></span> Dashboards
-            </NavLink>
-        </div>
-
-        <div class="nav-item px-3">
-            <NavLink class="nav-link" href="massdata">
-                <span class="bi bi-table-nav-menu" aria-hidden="true"></span> MassData
-            </NavLink>
-        </div>
-    </nav>
+<div class="nav-scrollable @(menuOpen ? "nav-open" : "")">
+    <DxTreeView CssClass="sidebar-tree">
+        <Nodes>
+            <DxTreeViewNode Text="Home" NavigateUrl="/" IconCssClass="dxi dxi-home" />
+            <DxTreeViewNode Text="Data Management" Expanded="true">
+                <Nodes>
+                    <DxTreeViewNode Text="Catalogs" NavigateUrl="/catalogs" IconCssClass="dxi dxi-folder" />
+                    <DxTreeViewNode Text="Dashboards" NavigateUrl="/dashboards" IconCssClass="dxi dxi-chart-bar" />
+                    <DxTreeViewNode Text="Mass Data" NavigateUrl="/massdata" IconCssClass="dxi dxi-table" />
+                </Nodes>
+            </DxTreeViewNode>
+        </Nodes>
+    </DxTreeView>
 </div>

+@code {
+    private bool menuOpen = false;
+    private void ToggleMenu() => menuOpen = !menuOpen;
+}
--- a/DbFirst.BlazorWebApp/Components/Layout/NavMenu.razor.css
+++ b/DbFirst.BlazorWebApp/Components/Layout/NavMenu.razor.css
@@ -1,117 +1,52 @@
-.navbar-toggler {
-    appearance: none;
-    cursor: pointer;
-    width: 3.5rem;
-    height: 2.5rem;
-    color: white;
-    position: absolute;
-    top: 0.5rem;
-    right: 1rem;
-    border: 1px solid rgba(255, 255, 255, 0.1);
-    background: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%28255, 255, 255, 0.55%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e") no-repeat center/1.75rem rgba(255, 255, 255, 0.1);
-}
-
-.navbar-toggler:checked {
-    background-color: rgba(255, 255, 255, 0.5);
-}
-
-.top-row {
+.nav-brand-row {
    height: 3.5rem;
-    background-color: rgba(0,0,0,0.4);
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 0 1rem;
+    border-bottom: 1px solid rgba(0, 0, 0, 0.12);
 }

-.navbar-brand {
-    font-size: 1.1rem;
+.nav-brand-link {
+    font-size: 1.05rem;
+    font-weight: 600;
+    text-decoration: none;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
 }

-.bi {
-    display: inline-block;
-    position: relative;
-    width: 1.25rem;
-    height: 1.25rem;
-    margin-right: 0.75rem;
-    top: -1px;
-    background-size: cover;
-}
-
-.bi-house-door-fill-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-house-door-fill' viewBox='0 0 16 16'%3E%3Cpath d='M6.5 14.5v-3.505c0-.245.25-.495.5-.495h2c.25 0 .5.25.5.5v3.5a.5.5 0 0 0 .5.5h4a.5.5 0 0 0 .5-.5v-7a.5.5 0 0 0-.146-.354L13 5.793V2.5a.5.5 0 0 0-.5-.5h-1a.5.5 0 0 0-.5.5v1.293L8.354 1.146a.5.5 0 0 0-.708 0l-6 6A.5.5 0 0 0 1.5 7.5v7a.5.5 0 0 0 .5.5h4a.5.5 0 0 0 .5-.5Z'/%3E%3C/svg%3E");
-}
-
-.bi-plus-square-fill-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-plus-square-fill' viewBox='0 0 16 16'%3E%3Cpath d='M2 0a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V2a2 2 0 0 0-2-2H2zm6.5 4.5v3h3a.5.5 0 0 1 0 1h-3v3a.5.5 0 0 1-1 0v-3h-3a.5.5 0 0 1 0-1h3v-3a.5.5 0 0 1 1 0z'/%3E%3C/svg%3E");
-}
-
-.bi-list-nested-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' class='bi bi-list-nested' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M4.5 11.5A.5.5 0 0 1 5 11h10a.5.5 0 0 1 0 1H5a.5.5 0 0 1-.5-.5zm-2-4A.5.5 0 0 1 3 7h10a.5.5 0 0 1 0 1H3a.5.5 0 0 1-.5-.5zm-2-4A.5.5 0 0 1 1 3h10a.5.5 0 0 1 0 1H1a.5.5 0 0 1-.5-.5z'/%3E%3C/svg%3E");
-}
-
-.bi-collection-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M2 3a.5.5 0 0 1 .5-.5h11a.5.5 0 0 1 .5.5v1H2V3z'/%3E%3Cpath d='M2 5h12v8a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5z'/%3E%3C/svg%3E");
-}
-
-.bi-speedometer-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M1 11a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V7a1 1 0 0 0-1-1H2a1 1 0 0 0-1 1v4zm5 0a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V3a1 1 0 0 0-1-1H7a1 1 0 0 0-1 1v8zm5 0a1 1 0 0 0 1 1h2a1 1 0 0 0 1-1V9a1 1 0 0 0-1-1h-2a1 1 0 0 0-1 1v2z'/%3E%3C/svg%3E");
-}
-
-.bi-table-nav-menu {
-    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='white' viewBox='0 0 16 16'%3E%3Cpath d='M1 2a1 1 0 0 1 1-1h12a1 1 0 0 1 1 1v12a1 1 0 0 1-1 1H2a1 1 0 0 1-1-1V2zm1 1v2h12V3H2zm12 3H2v2h12V6zm0 3H2v2h12V9zm0 3H2v1h12v-1z'/%3E%3C/svg%3E");
-}
-
-.nav-item {
-    font-size: 0.9rem;
-    padding-bottom: 0.5rem;
-}
-
-    .nav-item:first-of-type {
-        padding-top: 1rem;
-    }
-
-    .nav-item:last-of-type {
-        padding-bottom: 1rem;
-    }
-
-    .nav-item ::deep .nav-link {
-        color: #d7d7d7;
-        background: none;
-        border: none;
-        border-radius: 4px;
-        height: 3rem;
-        display: flex;
-        align-items: center;
-        line-height: 3rem;
-        width: 100%;
-    }
-
-.nav-item ::deep a.active {
-    background-color: rgba(255,255,255,0.37);
-    color: white;
-}
-
-.nav-item ::deep .nav-link:hover {
-    background-color: rgba(255,255,255,0.1);
-    color: white;
+.nav-toggle-btn {
+    display: block;
+    background: none;
+    border: none;
+    font-size: 1.4rem;
+    cursor: pointer;
+    padding: 0.25rem 0.5rem;
+    line-height: 1;
 }

 .nav-scrollable {
    display: none;
 }

-.navbar-toggler:checked ~ .nav-scrollable {
-    display: block;
+    .nav-scrollable.nav-open {
+        display: block;
+    }
+
+.sidebar-tree {
+    width: 100%;
 }

@media (min-width: 641px) {
-    .navbar-toggler {
+    .nav-toggle-btn {
        display: none;
    }

    .nav-scrollable {
-        /* Never collapse the sidebar for wide screens */
        display: block;
-
-        /* Allow sidebar to scroll for tall menus */
        height: calc(100vh - 3.5rem);
        overflow-y: auto;
    }
 }
+
--- a/DbFirst.BlazorWebApp/Components/MassDataGrid.razor
+++ b/DbFirst.BlazorWebApp/Components/MassDataGrid.razor
--- a/DbFirst.BlazorWebApp/Components/MassDataGrid.razor.css
+++ b/DbFirst.BlazorWebApp/Components/MassDataGrid.razor.css
@@ -0,0 +1,3 @@
+.massdata-edit-popup {
+    min-width: 720px;
+}
--- a/DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor
+++ b/DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor
@@ -1,49 +1,9 @@
@page "/dashboard"
@page "/dashboards/{DashboardId?}"
@implements IAsyncDisposable
-@inject Microsoft.Extensions.Configuration.IConfiguration Configuration
+@inject IOptions<AppSettings> AppSettingsOptions
@inject NavigationManager Navigation
-@inject DashboardApiClient DashboardApi
-
-<style>
-    .dashboard-shell {
-        display: flex;
-        gap: 0;
-        min-height: 800px;
-        border: 1px solid #e6e6e6;
-        border-radius: 6px;
-        overflow: hidden;
-        background: #fff;
-    }
-    .dashboard-nav {
-        width: 220px;
-        border-right: 1px solid #e6e6e6;
-        background: #fafafa;
-    }
-    .dashboard-nav-title {
-        padding: 0.75rem 1rem 0.5rem;
-        font-size: 0.7rem;
-        text-transform: uppercase;
-        letter-spacing: 0.08em;
-        color: #6c757d;
-        font-weight: 600;
-    }
-    .dashboard-nav-link {
-        display: block;
-        padding: 0.55rem 1rem;
-        color: inherit;
-        text-decoration: none;
-    }
-    .dashboard-nav-link.active {
-        background: #e9ecef;
-        font-weight: 600;
-    }
-    .dashboard-content {
-        flex: 1;
-        min-width: 0;
-        padding: 1rem;
-    }
-</style>
+@inject IDashboardApiClient DashboardApi

 <PageTitle>Dashboards</PageTitle>

@@ -85,12 +45,17 @@
    private string SelectedDashboardId { get; set; } = string.Empty;
    private string DashboardKey => $"{SelectedDashboardId}-{(IsDesigner ? "designer" : "viewer")}";

-    private string DashboardEndpoint => $"{Configuration["ApiBaseUrl"]?.TrimEnd('/')}/api/dashboard";
-    private string HubEndpoint => $"{Configuration["ApiBaseUrl"]?.TrimEnd('/')}/hubs/dashboards";
+    private string DashboardEndpoint => $"{AppSettingsOptions.Value.ApiBaseUrl.TrimEnd('/')}/api/dashboard";
+    private string HubEndpoint => $"{AppSettingsOptions.Value.ApiBaseUrl.TrimEnd('/')}/hubs/dashboards";

    protected override async Task OnInitializedAsync()
    {
        await RefreshDashboards();
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;

        _hubConnection = new HubConnectionBuilder()
            .WithUrl(HubEndpoint)
@@ -107,11 +72,6 @@

    protected override async Task OnParametersSetAsync()
    {
-        if (dashboards.Count == 0)
-        {
-            await RefreshDashboards();
-        }
-
        var requestedId = string.IsNullOrWhiteSpace(DashboardId) || string.Equals(DashboardId, "default", StringComparison.OrdinalIgnoreCase)
            ? null
            : DashboardId;
--- a/DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor.css
+++ b/DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor.css
@@ -0,0 +1,42 @@
+.dashboard-shell {
+    display: flex;
+    gap: 0;
+    min-height: 800px;
+    border: 1px solid #e6e6e6;
+    border-radius: 6px;
+    overflow: hidden;
+    background: #fff;
+}
+
+.dashboard-nav {
+    width: 220px;
+    border-right: 1px solid #e6e6e6;
+    background: #fafafa;
+}
+
+.dashboard-nav-title {
+    padding: 0.75rem 1rem 0.5rem;
+    font-size: 0.7rem;
+    text-transform: uppercase;
+    letter-spacing: 0.08em;
+    color: #6c757d;
+    font-weight: 600;
+}
+
+.dashboard-nav-link {
+    display: block;
+    padding: 0.55rem 1rem;
+    color: inherit;
+    text-decoration: none;
+}
+
+    .dashboard-nav-link.active {
+        background: #e9ecef;
+        font-weight: 600;
+    }
+
+.dashboard-content {
+    flex: 1;
+    min-width: 0;
+    padding: 1rem;
+}
--- a/DbFirst.BlazorWebApp/Components/Pages/Home.razor
+++ b/DbFirst.BlazorWebApp/Components/Pages/Home.razor
@@ -1,7 +1,43 @@
-@page "/"
+@rendermode InteractiveServer
+
+@page "/"

 <PageTitle>Home</PageTitle>

-<h1>Hello, world!</h1>
+<h1>Database first</h1>

-Welcome to your new app.
+<DxCarousel Width="100%"
+            Height="calc(100vh - 9rem)"
+            Data="@GetCarouselData()"
+            ImageSrcField="Source"
+            ImageAltField="AlternateText"
+            LoopNavigationEnabled="true"
+            SlideShowEnabled="true"
+            SlideShowDelay="3000"
+            PauseSlideShowOnHover="true"
+            ImageSizeMode="CarouselImageSizeMode.FitProportional">
+</DxCarousel>
+
+@code {
+    List<CarouselData> GetCarouselData()
+    {
+        return new List<CarouselData>
+        {
+            new CarouselData("/images/DbFirstBefehl.png", "DbFirstBefehl"),
+            new CarouselData("/images/CQRS - Katalog-Datenfluss.png", "CQRS - Katalog-Datenfluss"),
+            new CarouselData("/images/CQRS - Catalog Create, Update, Delete.png", "CQRS - Catalog Create, Update, Delete"),
+        };
+    }
+
+    public class CarouselData
+    {
+        public string Source { get; set; } = string.Empty;
+        public string AlternateText { get; set; } = string.Empty;
+
+        public CarouselData(string source, string alt)
+        {
+            Source = source;
+            AlternateText = alt;
+        }
+    }
+}
--- a/DbFirst.BlazorWebApp/Components/Routes.razor
+++ b/DbFirst.BlazorWebApp/Components/Routes.razor
@@ -1,4 +1,5 @@
-@rendermode InteractiveServer
+@rendermode @(new InteractiveServerRenderMode(prerender: false))
+

 <Router AppAssembly="typeof(Program).Assembly">
    <Found Context="routeData">
--- a/DbFirst.BlazorWebApp/Components/_Imports.razor
+++ b/DbFirst.BlazorWebApp/Components/_Imports.razor
@@ -1,17 +1,28 @@
@using System.Net.Http
@using System.Net.Http.Json
+@using System.Text.Json
+
@using Microsoft.AspNetCore.Components.Forms
+@using Microsoft.AspNetCore.Components.Rendering
@using Microsoft.AspNetCore.Components.Routing
@using Microsoft.AspNetCore.Components.Web
-@using static Microsoft.AspNetCore.Components.Web.RenderMode
@using Microsoft.AspNetCore.Components.Web.Virtualization
-@using Microsoft.JSInterop
@using Microsoft.AspNetCore.SignalR.Client
+@using Microsoft.JSInterop
+@using Microsoft.Extensions.Options
+@using static Microsoft.AspNetCore.Components.Web.RenderMode
+
@using DbFirst.BlazorWebApp
@using DbFirst.BlazorWebApp.Components
-@using DbFirst.BlazorWebApp.Models
+@using DbFirst.BlazorWebApp.Models.Grid
@using DbFirst.BlazorWebApp.Services
+@using DbFirst.Contracts.Catalogs
+@using DbFirst.Contracts.Dashboards
+@using DbFirst.Contracts.MassData
+@using DbFirst.Contracts.Layouts
+@using DbFirst.Domain
+
@using DevExpress.Blazor
@using DevExpress.DashboardBlazor
@using DevExpress.DashboardWeb
-@using DbFirst.BlazorWebApp
+@using DevExpress.Data.Filtering
--- a/DbFirst.BlazorWebApp/DbFirst.BlazorWebApp.csproj
+++ b/DbFirst.BlazorWebApp/DbFirst.BlazorWebApp.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk.Web">
+<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
@@ -11,10 +11,15 @@
    <PackageReference Include="DevExpress.Blazor.Dashboard" Version="25.2.3" />
    <PackageReference Include="DevExpress.Blazor.Themes" Version="25.2.3" />
    <PackageReference Include="DevExpress.Blazor.Themes.Fluent" Version="25.2.3" />
-  </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="DevExpress.Blazor" Version="25.2.3" />
    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="8.0.22" />
  </ItemGroup>

+  <ItemGroup>
+    <Folder Include="wwwroot\images\" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\DbFirst.Contracts\DbFirst.Contracts.csproj" />
+  </ItemGroup>
+
 </Project>
--- a/DbFirst.BlazorWebApp/Models/ApiResult.cs
+++ b/DbFirst.BlazorWebApp/Models/ApiResult.cs
@@ -0,0 +1,7 @@
+namespace DbFirst.BlazorWebApp.Models;
+
+public record ApiResult<T>(bool Success, T? Value, string? Error)
+{
+    public static ApiResult<T> Ok(T? value) => new(true, value, null);
+    public static ApiResult<T> Fail(string? error) => new(false, default, error);
+}
--- a/DbFirst.BlazorWebApp/Models/CatalogReadDto.cs
+++ b/DbFirst.BlazorWebApp/Models/CatalogReadDto.cs
@@ -1,12 +0,0 @@
-namespace DbFirst.BlazorWebApp.Models;
-
-public class CatalogReadDto
-{
-    public int Guid { get; set; }
-    public string CatTitle { get; set; } = null!;
-    public string CatString { get; set; } = null!;
-    public string AddedWho { get; set; } = null!;
-    public DateTime AddedWhen { get; set; }
-    public string? ChangedWho { get; set; }
-    public DateTime? ChangedWhen { get; set; }
-}
--- a/DbFirst.BlazorWebApp/Models/CatalogWriteDto.cs
+++ b/DbFirst.BlazorWebApp/Models/CatalogWriteDto.cs
@@ -1,8 +0,0 @@
-namespace DbFirst.BlazorWebApp.Models;
-
-public class CatalogWriteDto
-{
-    public string CatTitle { get; set; } = string.Empty;
-    public string CatString { get; set; } = string.Empty;
-    public int UpdateProcedure { get; set; }
-}
--- a/DbFirst.BlazorWebApp/Models/Grid/BandLayoutModels.cs
+++ b/DbFirst.BlazorWebApp/Models/Grid/BandLayoutModels.cs
@@ -0,0 +1,43 @@
+using DevExpress.Blazor;
+
+namespace DbFirst.BlazorWebApp.Models.Grid
+{
+    public class BandLayout
+    {
+        public List<BandDefinition> Bands { get; set; } = [];
+        public List<string> ColumnOrder { get; set; } = [];
+        public Dictionary<string, string?> ColumnWidths { get; set; } = new(StringComparer.OrdinalIgnoreCase);
+        public GridPersistentLayout? GridLayout { get; set; }
+        public SizeMode SizeMode { get; set; } = SizeMode.Medium;
+    }
+
+    public class BandDefinition
+    {
+        public string Id { get; set; } = string.Empty;
+        public string Caption { get; set; } = string.Empty;
+        public List<string> Columns { get; set; } = [];
+    }
+
+    public class BandOption
+    {
+        public string Id { get; set; } = string.Empty;
+        public string Caption { get; set; } = string.Empty;
+    }
+
+    public class ColumnDefinition
+    {
+        public string FieldName { get; init; } = string.Empty;
+        public string Caption { get; init; } = string.Empty;
+        public string? Width { get; set; }
+        public string? DisplayFormat { get; init; }
+        public bool ReadOnly { get; init; }
+        public ColumnFilterType FilterType { get; init; }
+    }
+
+    public enum ColumnFilterType
+    {
+        Text,
+        Bool,
+        Date
+    }
+}
--- a/DbFirst.BlazorWebApp/Models/LayoutDto.cs
+++ b/DbFirst.BlazorWebApp/Models/LayoutDto.cs
@@ -1,9 +0,0 @@
-namespace DbFirst.BlazorWebApp.Models;
-
-public class LayoutDto
-{
-    public string LayoutType { get; set; } = string.Empty;
-    public string LayoutKey { get; set; } = string.Empty;
-    public string UserName { get; set; } = string.Empty;
-    public string LayoutData { get; set; } = string.Empty;
-}
--- a/DbFirst.BlazorWebApp/Models/MassDataWriteDto.cs
+++ b/DbFirst.BlazorWebApp/Models/MassDataWriteDto.cs
@@ -1,9 +0,0 @@
-namespace DbFirst.BlazorWebApp.Models;
-
-public class MassDataWriteDto
-{
-    public string CustomerName { get; set; } = string.Empty;
-    public decimal Amount { get; set; }
-    public string Category { get; set; } = string.Empty;
-    public bool StatusFlag { get; set; }
-}
--- a/DbFirst.BlazorWebApp/Program.cs
+++ b/DbFirst.BlazorWebApp/Program.cs
@@ -1,3 +1,4 @@
+using DbFirst.BlazorWebApp;
 using DbFirst.BlazorWebApp.Components;
 using DbFirst.BlazorWebApp.Services;
 using DevExpress.Blazor;
@@ -8,36 +9,23 @@ var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddRazorComponents()
    .AddInteractiveServerComponents();

-builder.Services.AddDevExpressBlazor();
+builder.Services.AddDevExpressBlazor(options => options.BootstrapVersion = BootstrapVersion.v5);
+builder.Services.AddScoped<ThemeState>();
+builder.Services.AddScoped<BandLayoutService>();

 var apiBaseUrl = builder.Configuration["ApiBaseUrl"];
-if (!string.IsNullOrWhiteSpace(apiBaseUrl))
+builder.Services.Configure<AppSettings>(builder.Configuration);
+void ConfigureClient(HttpClient client)
 {
-    builder.Services.AddHttpClient<CatalogApiClient>(client =>
-    {
+    if (!string.IsNullOrWhiteSpace(apiBaseUrl))
        client.BaseAddress = new Uri(apiBaseUrl);
-    });
-    builder.Services.AddHttpClient<DashboardApiClient>(client =>
-    {
-        client.BaseAddress = new Uri(apiBaseUrl);
-    });
-    builder.Services.AddHttpClient<MassDataApiClient>(client =>
-    {
-        client.BaseAddress = new Uri(apiBaseUrl);
-    });
-    builder.Services.AddHttpClient<LayoutApiClient>(client =>
-    {
-        client.BaseAddress = new Uri(apiBaseUrl);
-    });
-}
-else
-{
-    builder.Services.AddHttpClient<CatalogApiClient>();
-    builder.Services.AddHttpClient<DashboardApiClient>();
-    builder.Services.AddHttpClient<MassDataApiClient>();
-    builder.Services.AddHttpClient<LayoutApiClient>();
 }

+builder.Services.AddHttpClient<ICatalogApiClient, CatalogApiClient>(ConfigureClient);
+builder.Services.AddHttpClient<IDashboardApiClient, DashboardApiClient>(ConfigureClient);
+builder.Services.AddHttpClient<IMassDataApiClient, MassDataApiClient>(ConfigureClient);
+builder.Services.AddHttpClient<ILayoutApiClient, LayoutApiClient>(ConfigureClient);
+
 var app = builder.Build();

 // Configure the HTTP request pipeline.
--- a/DbFirst.BlazorWebApp/Services/ApiClientHelper.cs
+++ b/DbFirst.BlazorWebApp/Services/ApiClientHelper.cs
@@ -0,0 +1,59 @@
+using System.Net;
+
+namespace DbFirst.BlazorWebApp.Services;
+
+internal sealed class ProblemDetailsDto
+{
+    public string? Type { get; set; }
+    public string? Title { get; set; }
+    public string? Detail { get; set; }
+}
+
+internal static class ApiClientHelper
+{
+    public static async Task<string> ReadErrorAsync(HttpResponseMessage response)
+    {
+        string? problemTitle = null;
+        string? problemDetail = null;
+
+        try
+        {
+            var problem = await response.Content.ReadFromJsonAsync<ProblemDetailsDto>();
+            if (problem != null)
+            {
+                problemTitle = problem.Title;
+                problemDetail = problem.Detail ?? problem.Type;
+            }
+        }
+        catch { }
+
+        var status = response.StatusCode;
+        var reason = response.ReasonPhrase;
+        var body = await response.Content.ReadAsStringAsync();
+
+        string? detail = problemDetail;
+        if (string.IsNullOrWhiteSpace(detail) && !string.IsNullOrWhiteSpace(body))
+            detail = body;
+
+        return status switch
+        {
+            HttpStatusCode.BadRequest => $"Eingabe ungültig{FormatSuffix(problemTitle, detail, reason)}",
+            HttpStatusCode.NotFound => $"Nicht gefunden{FormatSuffix(problemTitle, detail, reason)}",
+            HttpStatusCode.Conflict => $"Konflikt{FormatSuffix(problemTitle, detail, reason)}",
+            HttpStatusCode.Unauthorized => $"Nicht autorisiert{FormatSuffix(problemTitle, detail, reason)}",
+            HttpStatusCode.Forbidden => $"Nicht erlaubt{FormatSuffix(problemTitle, detail, reason)}",
+            HttpStatusCode.InternalServerError => $"Serverfehler{FormatSuffix(problemTitle, detail, reason)}",
+            _ => $"Fehler {(int)status} {reason ?? string.Empty}{FormatSuffix(problemTitle, detail, reason)}"
+        };
+    }
+
+    private static string FormatSuffix(string? title, string? detail, string? reason)
+    {
+        var parts = new List<string>();
+        if (!string.IsNullOrWhiteSpace(title)) parts.Add(title);
+        if (!string.IsNullOrWhiteSpace(detail)) parts.Add(detail);
+        if (parts.Count == 0 && !string.IsNullOrWhiteSpace(reason)) parts.Add(reason);
+        if (parts.Count == 0) return string.Empty;
+        return ": " + string.Join(" | ", parts);
+    }
+}
--- a/DbFirst.BlazorWebApp/Services/BandLayoutService.cs
+++ b/DbFirst.BlazorWebApp/Services/BandLayoutService.cs
@@ -0,0 +1,109 @@
+using DbFirst.BlazorWebApp.Models.Grid;
+using DbFirst.Contracts.Layouts;
+using Microsoft.JSInterop;
+using System.Text.Json;
+
+namespace DbFirst.BlazorWebApp.Services
+{
+    public class BandLayoutService(ILayoutApiClient layoutApi, IJSRuntime jsRuntime)
+    {
+        private const string LayoutUserStorageKey = "layoutUser";
+        private readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);
+        private string? _cachedLayoutUser;
+
+        public async Task<string> EnsureLayoutUserAsync()
+        {
+            if (!string.IsNullOrWhiteSpace(_cachedLayoutUser))
+                return _cachedLayoutUser;
+
+            var layoutUser = await jsRuntime.InvokeAsync<string?>("localStorage.getItem", LayoutUserStorageKey);
+            if (string.IsNullOrWhiteSpace(layoutUser))
+            {
+                layoutUser = Guid.NewGuid().ToString("N");
+                await jsRuntime.InvokeVoidAsync("localStorage.setItem", LayoutUserStorageKey, layoutUser);
+            }
+
+            _cachedLayoutUser = layoutUser;
+            return _cachedLayoutUser;
+        }
+
+        public async Task<BandLayout> LoadBandLayoutAsync(
+            string layoutType,
+            string layoutKey,
+            string layoutUser,
+            Dictionary<string, ColumnDefinition> columnLookup)
+        {
+            if (string.IsNullOrWhiteSpace(layoutUser))
+                return new BandLayout();
+
+            var stored = await layoutApi.GetAsync(layoutType, layoutKey, layoutUser);
+            if (stored != null && !string.IsNullOrWhiteSpace(stored.LayoutData))
+            {
+                var parsed = JsonSerializer.Deserialize<BandLayout>(stored.LayoutData, _jsonOptions);
+                return NormalizeBandLayout(parsed, columnLookup);
+            }
+
+            return new BandLayout();
+        }
+
+        public async Task SaveBandLayoutAsync(
+            string layoutType,
+            string layoutKey,
+            string layoutUser,
+            BandLayout bandLayout)
+        {
+            var layoutData = JsonSerializer.Serialize(bandLayout, _jsonOptions);
+            await layoutApi.UpsertAsync(new LayoutDto
+            {
+                LayoutType = layoutType,
+                LayoutKey = layoutKey,
+                UserName = layoutUser,
+                LayoutData = layoutData
+            });
+        }
+
+        public async Task ResetBandLayoutAsync(
+            string layoutType,
+            string layoutKey,
+            string layoutUser)
+        {
+            await layoutApi.DeleteAsync(layoutType, layoutKey, layoutUser);
+        }
+
+        public Dictionary<string, string> BuildAssignmentsFromLayout(BandLayout layout)
+        {
+            var assignments = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            foreach (var band in layout.Bands)
+            {
+                foreach (var column in band.Columns)
+                {
+                    assignments[column] = band.Id;
+                }
+            }
+            return assignments;
+        }
+
+        public BandLayout NormalizeBandLayout(
+            BandLayout? layout,
+            Dictionary<string, ColumnDefinition> columnLookup)
+        {
+            layout ??= new BandLayout();
+            layout.Bands ??= [];
+            layout.ColumnOrder ??= [];
+            layout.ColumnWidths ??= [];
+
+            foreach (var band in layout.Bands)
+            {
+                if (string.IsNullOrWhiteSpace(band.Id))
+                    band.Id = Guid.NewGuid().ToString("N");
+
+                if (string.IsNullOrWhiteSpace(band.Caption))
+                    band.Caption = "Band";
+
+                band.Columns = band.Columns?.Where(columnLookup.ContainsKey).ToList() ?? new List<string>();
+            }
+
+            return layout;
+        }
+    }
+}
--- a/DbFirst.BlazorWebApp/Services/CatalogApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/CatalogApiClient.cs
@@ -1,10 +1,9 @@
-using System.Net;
-using System.Net.Http.Json;
 using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.Catalogs;

 namespace DbFirst.BlazorWebApp.Services;

-public class CatalogApiClient
+public class CatalogApiClient : ICatalogApiClient
 {
    private readonly HttpClient _httpClient;
    private const string Endpoint = "api/catalogs";
@@ -14,123 +13,51 @@ public class CatalogApiClient
        _httpClient = httpClient;
    }

-    public async Task<List<CatalogReadDto>> GetAllAsync()
+    public async Task<List<CatalogReadDto>> GetAllAsync(CancellationToken ct = default)
    {
-        var result = await _httpClient.GetFromJsonAsync<List<CatalogReadDto>>(Endpoint);
-        return result ?? new List<CatalogReadDto>();
+        var result = await _httpClient.GetFromJsonAsync<List<CatalogReadDto>>(Endpoint, ct);
+        return result ?? [];
    }

-    public async Task<CatalogReadDto?> GetByIdAsync(int id)
+    public async Task<CatalogReadDto?> GetByIdAsync(int id, CancellationToken ct = default)
    {
-        return await _httpClient.GetFromJsonAsync<CatalogReadDto>($"{Endpoint}/{id}");
+        return await _httpClient.GetFromJsonAsync<CatalogReadDto>($"{Endpoint}/{id}", ct);
    }

-    public async Task<ApiResult<CatalogReadDto?>> CreateAsync(CatalogWriteDto dto)
+    public async Task<ApiResult<CatalogReadDto?>> CreateAsync(CatalogWriteDto dto, CancellationToken ct = default)
    {
-        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto);
+        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto, ct);
        if (response.IsSuccessStatusCode)
        {
            var payload = await response.Content.ReadFromJsonAsync<CatalogReadDto>();
            return ApiResult<CatalogReadDto?>.Ok(payload);
        }

-        var error = await ReadErrorAsync(response);
+        var error = await ApiClientHelper.ReadErrorAsync(response);
        return ApiResult<CatalogReadDto?>.Fail(error);
    }

-    public async Task<ApiResult<bool>> UpdateAsync(int id, CatalogWriteDto dto)
+    public async Task<ApiResult<bool>> UpdateAsync(int id, CatalogWriteDto dto, CancellationToken ct = default)
    {
-        var response = await _httpClient.PutAsJsonAsync($"{Endpoint}/{id}", dto);
+        var response = await _httpClient.PutAsJsonAsync($"{Endpoint}/{id}", dto, ct);
        if (response.IsSuccessStatusCode)
        {
            return ApiResult<bool>.Ok(true);
        }

-        var error = await ReadErrorAsync(response);
+        var error = await ApiClientHelper.ReadErrorAsync(response);
        return ApiResult<bool>.Fail(error);
    }

-    public async Task<ApiResult<bool>> DeleteAsync(int id)
+    public async Task<ApiResult<bool>> DeleteAsync(int id, CancellationToken ct = default)
    {
-        var response = await _httpClient.DeleteAsync($"{Endpoint}/{id}");
+        var response = await _httpClient.DeleteAsync($"{Endpoint}/{id}", ct);
        if (response.IsSuccessStatusCode)
        {
            return ApiResult<bool>.Ok(true);
        }

-        var error = await ReadErrorAsync(response);
+        var error = await ApiClientHelper.ReadErrorAsync(response);
        return ApiResult<bool>.Fail(error);
    }
-
-    private static async Task<string> ReadErrorAsync(HttpResponseMessage response)
-    {
-        string? problemTitle = null;
-        string? problemDetail = null;
-
-        try
-        {
-            var problem = await response.Content.ReadFromJsonAsync<ProblemDetailsDto>();
-            if (problem != null)
-            {
-                problemTitle = problem.Title;
-                problemDetail = problem.Detail ?? problem.Type;
-            }
-        }
-        catch
-        {
-        }
-
-        var status = response.StatusCode;
-        var reason = response.ReasonPhrase;
-        var body = await response.Content.ReadAsStringAsync();
-
-        string? detail = problemDetail;
-        if (string.IsNullOrWhiteSpace(detail) && !string.IsNullOrWhiteSpace(body))
-        {
-            detail = body;
-        }
-
-        if (status == HttpStatusCode.Conflict)
-        {
-            return "Datensatz existiert bereits. Bitte wählen Sie einen anderen Titel.";
-        }
-        if (status == HttpStatusCode.BadRequest && (detail?.Contains("CatTitle cannot be changed", StringComparison.OrdinalIgnoreCase) ?? false))
-        {
-            return "Titel kann nicht geändert werden.";
-        }
-
-        return status switch
-        {
-            HttpStatusCode.BadRequest => $"Eingabe ungültig{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.NotFound => $"Nicht gefunden{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Conflict => $"Konflikt{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Unauthorized => $"Nicht autorisiert{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.Forbidden => $"Nicht erlaubt{FormatSuffix(problemTitle, detail, reason)}",
-            HttpStatusCode.InternalServerError => $"Serverfehler{FormatSuffix(problemTitle, detail, reason)}",
-            _ => $"Fehler {(int)status} {reason ?? string.Empty}{FormatSuffix(problemTitle, detail, reason)}"
-        };
-    }
-
-    private static string FormatSuffix(string? title, string? detail, string? reason)
-    {
-        var parts = new List<string>();
-        if (!string.IsNullOrWhiteSpace(title)) parts.Add(title);
-        if (!string.IsNullOrWhiteSpace(detail)) parts.Add(detail);
-        if (parts.Count == 0 && !string.IsNullOrWhiteSpace(reason)) parts.Add(reason);
-        if (parts.Count == 0) return string.Empty;
-        return ": " + string.Join(" | ", parts);
-    }
-}
-
-public record ApiResult<T>(bool Success, T? Value, string? Error)
-{
-    public static ApiResult<T> Ok(T? value) => new(true, value, null);
-    public static ApiResult<T> Fail(string? error) => new(false, default, error);
-}
-
-internal sealed class ProblemDetailsDto
-{
-    public string? Type { get; set; }
-    public string? Title { get; set; }
-    public string? Detail { get; set; }
-}
+}
--- a/DbFirst.BlazorWebApp/Services/DashboardApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/DashboardApiClient.cs
@@ -1,9 +1,8 @@
-using System.Net.Http.Json;
-using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.Dashboards;

 namespace DbFirst.BlazorWebApp.Services;

-public class DashboardApiClient
+public class DashboardApiClient : IDashboardApiClient
 {
    private readonly HttpClient _httpClient;
    private const string Endpoint = "api/dashboard/dashboards";
@@ -13,9 +12,9 @@ public class DashboardApiClient
        _httpClient = httpClient;
    }

-    public async Task<List<DashboardInfoDto>> GetAllAsync()
+    public async Task<List<DashboardInfoDto>> GetAllAsync(CancellationToken ct = default)
    {
-        var result = await _httpClient.GetFromJsonAsync<List<DashboardInfoDto>>(Endpoint);
-        return result ?? new List<DashboardInfoDto>();
+        var result = await _httpClient.GetFromJsonAsync<List<DashboardInfoDto>>(Endpoint, ct);
+        return result ?? [];
    }
 }
--- a/DbFirst.BlazorWebApp/Services/ICatalogApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/ICatalogApiClient.cs
@@ -0,0 +1,13 @@
+using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.Catalogs;
+
+namespace DbFirst.BlazorWebApp.Services;
+
+public interface ICatalogApiClient
+{
+    Task<List<CatalogReadDto>> GetAllAsync(CancellationToken ct = default);
+    Task<CatalogReadDto?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<ApiResult<CatalogReadDto?>> CreateAsync(CatalogWriteDto dto, CancellationToken ct = default);
+    Task<ApiResult<bool>> UpdateAsync(int id, CatalogWriteDto dto, CancellationToken ct = default);
+    Task<ApiResult<bool>> DeleteAsync(int id, CancellationToken ct = default);
+}
--- a/DbFirst.BlazorWebApp/Services/IDashboardApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/IDashboardApiClient.cs
@@ -0,0 +1,9 @@
+using DbFirst.Contracts.Dashboards;
+
+namespace DbFirst.BlazorWebApp.Services
+{
+    public interface IDashboardApiClient
+    {
+        Task<List<DashboardInfoDto>> GetAllAsync(CancellationToken ct = default);
+    }
+}
--- a/DbFirst.BlazorWebApp/Services/ILayoutApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/ILayoutApiClient.cs
@@ -0,0 +1,11 @@
+using DbFirst.Contracts.Layouts;
+
+namespace DbFirst.BlazorWebApp.Services
+{
+    public interface ILayoutApiClient
+    {
+        Task<LayoutDto?> GetAsync(string layoutType, string layoutKey, string userName, CancellationToken ct = default);
+        Task<LayoutDto> UpsertAsync(LayoutDto dto, CancellationToken ct = default);
+        Task DeleteAsync(string layoutType, string layoutKey, string userName, CancellationToken ct = default);
+    }
+}
--- a/DbFirst.BlazorWebApp/Services/IMassDataApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/IMassDataApiClient.cs
@@ -0,0 +1,13 @@
+using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.MassData;
+
+namespace DbFirst.BlazorWebApp.Services
+{
+    public interface IMassDataApiClient
+    {
+        Task<int> GetCountAsync(CancellationToken ct = default);
+        Task<List<MassDataReadDto>> GetAllAsync(int? skip, int? take, CancellationToken ct = default);
+        Task<ApiResult<MassDataReadDto?>> UpsertAsync(MassDataWriteDto dto, CancellationToken ct = default);
+        Task<MassDataReadDto?> GetByCustomerNameAsync(string customerName, CancellationToken ct = default);
+    }
+}
--- a/DbFirst.BlazorWebApp/Services/LayoutApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/LayoutApiClient.cs
@@ -1,9 +1,8 @@
-using System.Net.Http.Json;
-using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.Layouts;

 namespace DbFirst.BlazorWebApp.Services;

-public class LayoutApiClient
+public class LayoutApiClient : ILayoutApiClient
 {
    private readonly HttpClient _httpClient;
    private const string Endpoint = "api/layouts";
@@ -13,10 +12,10 @@ public class LayoutApiClient
        _httpClient = httpClient;
    }

-    public async Task<LayoutDto?> GetAsync(string layoutType, string layoutKey, string userName)
+    public async Task<LayoutDto?> GetAsync(string layoutType, string layoutKey, string userName, CancellationToken ct = default)
    {
        var url = $"{Endpoint}?layoutType={Uri.EscapeDataString(layoutType)}&layoutKey={Uri.EscapeDataString(layoutKey)}&userName={Uri.EscapeDataString(userName)}";
-        var response = await _httpClient.GetAsync(url);
+        var response = await _httpClient.GetAsync(url, ct);
        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
        {
            return null;
@@ -26,12 +25,12 @@ public class LayoutApiClient
        return await response.Content.ReadFromJsonAsync<LayoutDto>();
    }

-    public async Task<LayoutDto> UpsertAsync(LayoutDto dto)
+    public async Task<LayoutDto> UpsertAsync(LayoutDto dto, CancellationToken ct = default)
    {
-        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto);
+        var response = await _httpClient.PostAsJsonAsync(Endpoint, dto, ct);
        if (!response.IsSuccessStatusCode)
        {
-            var detail = await ReadErrorAsync(response);
+            var detail = await ApiClientHelper.ReadErrorAsync(response);
            throw new InvalidOperationException(detail);
        }

@@ -39,21 +38,10 @@ public class LayoutApiClient
        return payload ?? dto;
    }

-    private static async Task<string> ReadErrorAsync(HttpResponseMessage response)
-    {
-        var body = await response.Content.ReadAsStringAsync();
-        if (!string.IsNullOrWhiteSpace(body))
-        {
-            return body;
-        }
-
-        return $"{(int)response.StatusCode} {response.ReasonPhrase}".Trim();
-    }
-
-    public async Task DeleteAsync(string layoutType, string layoutKey, string userName)
+    public async Task DeleteAsync(string layoutType, string layoutKey, string userName, CancellationToken ct = default)
    {
        var url = $"{Endpoint}?layoutType={Uri.EscapeDataString(layoutType)}&layoutKey={Uri.EscapeDataString(layoutKey)}&userName={Uri.EscapeDataString(userName)}";
-        var response = await _httpClient.DeleteAsync(url);
+        var response = await _httpClient.DeleteAsync(url, ct);
        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
        {
            return;
--- a/DbFirst.BlazorWebApp/Services/MassDataApiClient.cs
+++ b/DbFirst.BlazorWebApp/Services/MassDataApiClient.cs
@@ -1,9 +1,9 @@
-using System.Net.Http.Json;
 using DbFirst.BlazorWebApp.Models;
+using DbFirst.Contracts.MassData;

 namespace DbFirst.BlazorWebApp.Services;

-public class MassDataApiClient
+public class MassDataApiClient : IMassDataApiClient
 {
    private readonly HttpClient _httpClient;
    private const string Endpoint = "api/massdata";
@@ -13,13 +13,13 @@ public class MassDataApiClient
        _httpClient = httpClient;
    }

-    public async Task<int> GetCountAsync()
+    public async Task<int> GetCountAsync(CancellationToken ct = default)
    {
-        var result = await _httpClient.GetFromJsonAsync<int?>("api/massdata/count");
+        var result = await _httpClient.GetFromJsonAsync<int?>("api/massdata/count", ct);
        return result ?? 0;
    }

-    public async Task<List<MassDataReadDto>> GetAllAsync(int? skip, int? take)
+    public async Task<List<MassDataReadDto>> GetAllAsync(int? skip, int? take, CancellationToken ct = default)
    {
        var query = new List<string>();
        if (skip.HasValue)
@@ -32,26 +32,31 @@ public class MassDataApiClient
        }

        var url = query.Count == 0 ? Endpoint : $"{Endpoint}?{string.Join("&", query)}";
-        var result = await _httpClient.GetFromJsonAsync<List<MassDataReadDto>>(url);
-        return result ?? new List<MassDataReadDto>();
+        var result = await _httpClient.GetFromJsonAsync<List<MassDataReadDto>>(url, ct);
+        return result ?? [];
    }

-    public async Task<MassDataReadDto> UpsertAsync(MassDataWriteDto dto)
+    public async Task<ApiResult<MassDataReadDto?>> UpsertAsync(MassDataWriteDto dto, CancellationToken ct = default)
    {
-        var response = await _httpClient.PostAsJsonAsync($"{Endpoint}/upsert", dto);
-        response.EnsureSuccessStatusCode();
-        var payload = await response.Content.ReadFromJsonAsync<MassDataReadDto>();
-        return payload ?? new MassDataReadDto();
+        var response = await _httpClient.PostAsJsonAsync($"{Endpoint}/upsert", dto, ct);
+        if (response.IsSuccessStatusCode)
+        {
+            var payload = await response.Content.ReadFromJsonAsync<MassDataReadDto>();
+            return ApiResult<MassDataReadDto?>.Ok(payload);
+        }
+
+        var error = await ApiClientHelper.ReadErrorAsync(response);
+        return ApiResult<MassDataReadDto?>.Fail(error);
    }

-    public async Task<MassDataReadDto?> GetByCustomerNameAsync(string customerName)
+    public async Task<MassDataReadDto?> GetByCustomerNameAsync(string customerName, CancellationToken ct = default)
    {
        if (string.IsNullOrWhiteSpace(customerName))
        {
            return null;
        }

-        var response = await _httpClient.GetAsync($"{Endpoint}/{Uri.EscapeDataString(customerName)}");
+        var response = await _httpClient.GetAsync($"{Endpoint}/{Uri.EscapeDataString(customerName)}", ct);
        if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
        {
            return null;
--- a/DbFirst.BlazorWebApp/Services/ThemeState.cs
+++ b/DbFirst.BlazorWebApp/Services/ThemeState.cs
@@ -0,0 +1,65 @@
+using DevExpress.Blazor;
+
+namespace DbFirst.BlazorWebApp.Services;
+
+public class ThemeState
+{
+    private readonly IThemeChangeService themeChangeService;
+
+    public ThemeState(IThemeChangeService themeChangeService)
+    {
+        this.themeChangeService = themeChangeService;
+    }
+
+    public bool IsDarkMode { get; private set; }
+    public string CurrentThemeName { get; private set; } = "Fluent";
+
+    /// <summary>
+    /// Themes die eine native DevExpress Dark-Variante besitzen:
+    ///   - Fluent  ? Themes.Fluent.Clone(ThemeMode.Dark), verwendet --DS-* Token-System
+    ///   - BlazingBerry ? Themes.BlazingDark
+    /// Alle anderen Themes (Purple, OfficeWhite, BootstrapExternal) haben keine offizielle
+    /// Dark-Variante; dort übernehmen CSS-Overrides auf --dxbl-grid-* Variablen die Arbeit.
+    /// </summary>
+    public bool IsNativeDarkTheme => IsDarkMode &&
+        (CurrentThemeName == "Fluent" || CurrentThemeName == "BlazingBerry");
+
+    public static readonly List<string> AvailableThemes = ["Fluent", "BlazingBerry", "Purple", "OfficeWhite", "BootstrapExternal"];
+
+    public event Action? OnChange;
+
+    public void SetTheme(string themeName)
+    {
+        if (CurrentThemeName == themeName) return;
+        CurrentThemeName = themeName;
+        ApplyTheme();
+        OnChange?.Invoke();
+    }
+
+    public void SetDarkMode(bool isDarkMode)
+    {
+        if (IsDarkMode == isDarkMode) return;
+        IsDarkMode = isDarkMode;
+        ApplyTheme();
+        OnChange?.Invoke();
+    }
+
+    private void ApplyTheme()
+    {
+        if (CurrentThemeName == "Fluent")
+        {
+            var theme = Themes.Fluent.Clone(properties =>
+            {
+                properties.Mode = IsDarkMode ? ThemeMode.Dark : ThemeMode.Light;
+                properties.ApplyToPageElements = true;
+            });
+            themeChangeService.SetTheme(theme);
+        }
+        else if (CurrentThemeName == "BlazingBerry") themeChangeService.SetTheme(IsDarkMode ? Themes.BlazingDark : Themes.BlazingBerry);
+        else if (CurrentThemeName == "Purple")           themeChangeService.SetTheme(Themes.Purple);
+        else if (CurrentThemeName == "OfficeWhite")      themeChangeService.SetTheme(Themes.OfficeWhite);
+        else if (CurrentThemeName == "BootstrapExternal") themeChangeService.SetTheme(Themes.BootstrapExternal);
+        else
+            themeChangeService.SetTheme(Themes.Fluent);
+    }
+}
--- a/DbFirst.BlazorWebApp/appsettings.Development.json
+++ b/DbFirst.BlazorWebApp/appsettings.Development.json
@@ -5,5 +5,11 @@
      "Microsoft.AspNetCore": "Warning"
    }
  },
-  "ApiBaseUrl": "https://localhost:7204/"
+  "ApiBaseUrl": "https://localhost:7204/",
+  "BrowserLink": {
+    "Enabled": false
+  },
+  "DetailedErrors": true
 }
+
+
--- a/DbFirst.BlazorWebApp/wwwroot/app.css
+++ b/DbFirst.BlazorWebApp/wwwroot/app.css
@@ -1,11 +1,37 @@
+:root {
+    --global-size: 16px;
+}
+
 html, body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
+    font-size: var(--global-size);
+}
+
+/* Theme-Variablen */
+.app-light {
+    --band-editor-bg: #f8f9fa;
+    --band-editor-border: #dee2e6;
+    --band-toggle-hover-bg: #e9ecef;
+    --grid-stripe-bg: rgba(0, 0, 0, 0.03);
+}
+
+.app-dark {
+    background-color: #1b1b1b;
+    color: #f1f1f1;
+    --band-editor-bg: #2d2d2d;
+    --band-editor-border: #444444;
+    --band-toggle-hover-bg: #3a3a3a;
+    --grid-stripe-bg: rgba(255, 255, 255, 0.04);
 }

 a, .btn-link {
    color: #006bb7;
 }

+.app-dark a, .app-dark .btn-link {
+    color: #6cb6ff;
+}
+
 .btn-primary {
    color: #fff;
    background-color: #1b6ec2;
@@ -13,7 +39,7 @@ a, .btn-link {
 }

 .btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
-  box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
+    box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
 }

 .content {
@@ -37,7 +63,7 @@ h1:focus {
 }

 .blazor-error-boundary {
-    background: url(data:image/svg+xml;base64,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) no-repeat 1rem/1.8rem, #b32121;
+    background: url(data:image/svg+xml;base64,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) no-repeat 1rem/1.8rem, #b32121;
    padding: 1rem 1rem 1rem 3.7rem;
    color: white;
 }
@@ -49,3 +75,216 @@ h1:focus {
 .darker-border-checkbox.form-check-input {
    border-color: #929292;
 }
+
+/* Grid Band-Editor */
+.band-editor {
+    margin-top: 4px;
+    margin-bottom: 16px;
+    border: 1px solid var(--band-editor-border);
+    border-radius: 4px;
+    background-color: var(--band-editor-bg);
+    overflow: hidden;
+}
+
+.band-editor-toggle {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    width: 100%;
+    padding: 8px 12px;
+    background: none;
+    border: none;
+    cursor: pointer;
+    font-size: inherit;
+    color: inherit;
+    text-align: left;
+}
+
+    .band-editor-toggle:hover {
+        background-color: var(--band-toggle-hover-bg);
+    }
+
+.band-editor-toggle-icon {
+    font-size: 0.7rem;
+    transition: transform 0.2s ease;
+    display: inline-block;
+}
+
+    .band-editor-toggle-icon.expanded {
+        transform: rotate(90deg);
+    }
+
+.band-editor-body {
+    display: flex;
+    flex-direction: column;
+    gap: 12px;
+    padding: 0 12px 12px 12px;
+}
+
+.band-controls {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 8px;
+    align-items: center;
+}
+
+.band-row {
+    display: flex;
+    gap: 8px;
+    align-items: center;
+}
+
+.band-columns {
+    max-width: 720px;
+    margin-top: 4px;
+}
+
+.grid-section {
+    margin-top: 4px;
+}
+
+/* Grid Zebra-Striping */
+dxbl-grid tbody tr:nth-child(even) td {
+    background-color: var(--grid-stripe-bg) !important;
+}
+
+/* ?? Dark-Mode-Overrides für nicht-native Themes ?????????????????????????????
+   Strategie: CSS-Custom-Properties werden von DevExpress DIREKT auf den
+   Komponenten-Elementen definiert (z. B. --dxbl-popup-bg:#fff auf .dxbl-modal).
+   Eine geerbte Variable aus html.dx-dark würde durch die direkte Zuweisung
+   überschrieben. Deshalb targeten wir exakt dieselben Elemente, aber mit einem
+   zusätzlichen Vorfahren-Selektor (html.dx-dark) für höhere Spezifizität:
+     html.dx-dark .dxbl-modal = (0,2,1)  >  .dxbl-modal = (0,1,0)  ?
+   html.dx-dark wird per JS gesetzt, wenn IsDarkMode && !IsNativeDarkTheme.
+?? */
+
+/* Popup / Modal (CRUD-Dialoge) – Variablen-Quelle: .dxbl-modal */
+html.dx-dark .dxbl-modal {
+    --dxbl-popup-bg: #2d2d2d;
+    --dxbl-popup-color: #e8e8e8;
+    --dxbl-popup-border-color: #555;
+    --dxbl-popup-header-bg: #333;
+    --dxbl-popup-header-color: #e8e8e8;
+    --dxbl-popup-footer-bg: #333;
+    --dxbl-popup-footer-color: #e8e8e8;
+}
+
+/* Flyout (Column Chooser, Filter-Panel) – Variablen-Quelle: .dxbl-flyout */
+html.dx-dark .dxbl-flyout {
+    --dxbl-flyout-bg: #2d2d2d;
+    --dxbl-flyout-color: #e8e8e8;
+    --dxbl-flyout-border-color: #555;
+    --dxbl-flyout-header-bg: #333;
+    --dxbl-flyout-header-color: #e8e8e8;
+    --dxbl-flyout-footer-bg: #333;
+}
+
+/* Dropdown (ComboBox-Klappliste, Band-Dropdowns) – Quelle: .dxbl-dropdown */
+html.dx-dark .dxbl-dropdown,
+html.dx-dark .dxbl-itemlist-dropdown {
+    --dxbl-dropdown-bg: #2d2d2d;
+    --dxbl-dropdown-color: #e8e8e8;
+    --dxbl-dropdown-border-color: #555;
+    --dxbl-dropdown-header-bg: #333;
+    --dxbl-dropdown-footer-bg: #333;
+}
+
+/* Edit-Dropdown (ComboBox-Popup wenn als Modal gerendert) – Quelle: .dxbl-edit-dropdown */
+html.dx-dark .dxbl-edit-dropdown {
+    --dxbl-edit-dropdown-bg: #2d2d2d;
+    --dxbl-edit-dropdown-color: #e8e8e8;
+    --dxbl-edit-dropdown-border-color: #555;
+}
+
+/* ListBox (Einträge in Dropdowns) – Quelle: .dxbl-list-box */
+html.dx-dark .dxbl-list-box,
+html.dx-dark .dxbl-list-box-render-container {
+    --dxbl-list-box-bg: #2d2d2d;
+    --dxbl-list-box-color: #e8e8e8;
+    --dxbl-list-box-border-color: #555;
+    --dxbl-list-box-item-hover-bg: #3a3a3a;
+    --dxbl-list-box-item-hover-color: #e8e8e8;
+}
+
+/* TextEdit / ComboBox – Eingabefeld – Quelle: .dxbl-text-edit */
+html.dx-dark .dxbl-text-edit {
+    --dxbl-text-edit-bg: #2d2d2d;
+    --dxbl-text-edit-color: #e8e8e8;
+    --dxbl-text-edit-border-color: #555;
+    --dxbl-text-edit-btn-bg: #3a3a3a;
+    --dxbl-text-edit-btn-color: #e8e8e8;
+    --dxbl-text-edit-btn-hover-bg: #444;
+    --dxbl-text-edit-btn-hover-color: #e8e8e8;
+}
+
+/* Buttons */
+html.dx-dark .dxbl-btn {
+    --dxbl-btn-color: #e8e8e8;
+    --dxbl-btn-bg: #3a3a3a;
+    --dxbl-btn-border-color: #555;
+    --dxbl-btn-hover-bg: #444;
+    --dxbl-btn-hover-color: #e8e8e8;
+    --dxbl-btn-hover-border-color: #666;
+}
+
+/* FormLayout */
+html.dx-dark .dxbl-fl {
+    --dxbl-fl-caption-color: #bbb;
+    --dxbl-fl-group-bg: #242424;
+    --dxbl-fl-group-color: #e8e8e8;
+}
+
+/* Grid */
+html.dx-dark .dxbl-grid {
+    background-color: #242424;
+    color: #e8e8e8;
+    border-color: #444;
+}
+
+html.dx-dark .dxbl-grid > .dxbl-scroll-viewer,
+html.dx-dark .dxbl-grid > .dxbl-grid-top-panel {
+    background-color: #242424;
+    color: #e8e8e8;
+}
+
+/* MassData-spezifisch */
+.page-size-selector {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    flex-wrap: nowrap;
+    margin-bottom: 12px;
+}
+
+.page-size-label {
+    white-space: nowrap;
+}
+
+.page-size-combo {
+    width: 13ch;
+    min-width: 13ch;
+    max-width: 13ch;
+}
+
+    .page-size-combo input {
+        text-align: left;
+    }
+
+.pager-container {
+    display: flex;
+    justify-content: center;
+    margin-top: 12px;
+    margin-bottom: 16px;
+}
+
+/* Lade-Spinner */
+.loading-container {
+    min-height: 160px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+}
+
+.top-row .btn-gap {
+    margin-left: 8px;
+}
--- a/Show More
+++ b/Show More