Move LayoutDto to its own file and update namespace

Separated LayoutDto from LayoutsController.cs into LayoutDto.cs and set its namespace to DbFirst.Application.Layouts for better code organization and maintainability.

DbFirst.API/Controllers/CatalogsController.cs

@@ -50,17 +50,6 @@ public class CatalogsController : ControllerBase
     [HttpPut("{id:int}")]
     public async Task<ActionResult<CatalogReadDto>> Update(int id, 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)
         {

DbFirst.API/Controllers/LayoutsController.cs

@@ -2,6 +2,7 @@ using System.Text;
 using DbFirst.Application.Repositories;
 using DbFirst.Domain.Entities;
 using Microsoft.AspNetCore.Mvc;
+using DbFirst.Application.Layouts;
 
 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;
-    }
 }

DbFirst.API/Program.cs

@@ -2,11 +2,9 @@ using DbFirst.API.Middleware;
 using DbFirst.API.Dashboards;
 using DbFirst.API.Hubs;
 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;
@@ -51,10 +49,6 @@ 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>();

DbFirst.Application/Catalogs/Commands/UpdateCatalogHandler.cs

@@ -25,18 +25,20 @@ 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, request.Dto.UpdateProcedure, cancellationToken);
-        var updated = await _repository.UpdateAsync(request.Id, entity, procedure, cancellationToken);
         return updated == null ? null : _mapper.Map<CatalogReadDto>(updated);
     }
 }

DbFirst.Application/Layouts/LayoutDto.cs

@@ -0,0 +1,9 @@
+namespace DbFirst.Application.Layouts;
+
+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;
+}

DbFirst.BlazorWebApp/AppSettings.cs

@@ -0,0 +1,6 @@
+namespace DbFirst.BlazorWebApp;
+
+public class AppSettings
+{
+    public string ApiBaseUrl { get; set; } = string.Empty;
+}

DbFirst.BlazorWebApp/Components/App.razor

@@ -5,10 +5,7 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <base href="/" />
-    @DxResourceManager.RegisterTheme(Themes.Fluent.Clone(properties =>
+    @DxResourceManager.RegisterTheme(Themes.Fluent)
-    {
-        properties.ApplyToPageElements = true;
-    }))
     @DxResourceManager.RegisterScripts()
 
     <link href="_content/DevExpress.Blazor.Dashboard/ace.css" rel="stylesheet" />
@@ -21,6 +18,7 @@
     <link href="_content/DevExpress.Blazor.Dashboard/dx-dashboard.light.min.css" rel="stylesheet" />
 
     <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" />

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; }
+}

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;
+    }
+
+}

DbFirst.BlazorWebApp/Components/CatalogsGrid.razor

@@ -1,5 +1,5 @@
-@inject CatalogApiClient Api
+@inherits BandGridBase<CatalogReadDto>
-@inject BandLayoutService BandLayoutService
+@inject ICatalogApiClient Api
 
 @if (!string.IsNullOrWhiteSpace(errorMessage))
 {
@@ -24,47 +24,21 @@ else if (items.Count == 0)
 }
 else
 {
-    <div class="band-editor">
+    <BandEditor Bands="@bandLayout.Bands"
-        <button class="band-editor-toggle" @onclick="() => bandEditorExpanded = !bandEditorExpanded">
+                BandOptions="@bandOptions"
-            <span class="band-editor-toggle-icon @(bandEditorExpanded ? "expanded" : "")">&#9658;</span>
+                Columns="@ColumnDefinitions"
-            <span>Layout</span>
+                GetColumnBand="GetColumnBand"
-        </button>
+                CanSave="@CanSaveBandLayout"
-        @if (bandEditorExpanded)
+                OnAddBand="AddBand"
-        {
+                OnSaveLayout="SaveLayoutWithFeedbackAsync"
-            <div class="band-editor-body">
+                OnResetLayout="ResetLayoutWithFeedbackAsync"
-                <div class="band-controls">
+                OnRemoveBand="RemoveBand"
-                    <DxButton Text="Band hinzufügen" Click="AddBand" />
+                OnBandCaptionChanged="@(args => UpdateBandCaption(args.Band, args.Value))"
-                    <DxButton Text="Layout speichern" Click="SaveLayoutAsync" Enabled="@CanSaveBandLayout" />
+                OnColumnBandChanged="@(args => UpdateColumnBand(args.FieldName, args.BandId))" />
-                    <DxButton Text="Layout zurücksetzen" Click="ResetLayoutAsync" />
-                </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>
 
     <div class="grid-section">
         <DxGrid Data="@items"
+                ColumnChooserButtonDisplayMode="GridColumnChooserButtonDisplayMode.Always"
                 TItem="CatalogReadDto"
                 KeyFieldName="@nameof(CatalogReadDto.Guid)"
                 SizeMode="@_sizeMode"
@@ -85,9 +59,42 @@ else
                 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)"
@@ -142,35 +149,21 @@ else
 
 @code {
     private List<CatalogReadDto> items = new();
-    private bool isLoading;
-    private bool hasLoaded;
-    private string? errorMessage;
-    private string? infoMessage;
-    private EditContext? editContext;
-    private ValidationMessageStore? validationMessageStore;
-    private IGrid? gridRef;
     private int? focusedRowKey;
-    private string popupHeaderText = "Edit";
-    private const string LayoutType = "GRID_BANDS";
-    private const string LayoutKey = "CatalogsGrid";
-    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 bool gridLayoutApplied;
-    private bool bandEditorExpanded;
 
-    private List<ColumnDefinition> columnDefinitions = new()
+    protected override string LayoutKey => "CatalogsGrid";
-    {
+    protected override bool ShowCommandColumn => false;
-        new() { FieldName = nameof(CatalogReadDto.Guid), Caption = "Id", Width = "140px", FilterType = ColumnFilterType.Text },
+
-        new() { FieldName = nameof(CatalogReadDto.CatTitle), Caption = "Titel", FilterType = ColumnFilterType.Text },
+    protected override List<ColumnDefinition> ColumnDefinitions { get; } = new()
-        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.Guid),       Caption = "Id",          Width = "140px", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.AddedWhen), Caption = "Angelegt am", ReadOnly = true, FilterType = ColumnFilterType.Date },
+    new() { FieldName = nameof(CatalogReadDto.CatTitle),   Caption = "Titel",                        FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWho), Caption = "Geändert von", ReadOnly = true, FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(CatalogReadDto.CatString),  Caption = "String",                       FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(CatalogReadDto.ChangedWhen), Caption = "Geändert am", ReadOnly = true, FilterType = ColumnFilterType.Date }
+    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()
     {
@@ -178,44 +171,15 @@ else
         new() { Value = 1, Text = "PRTBMY_CATALOG_SAVE" }
     };
 
-    private bool CanSaveBandLayout => !string.IsNullOrWhiteSpace(layoutUser);
-
-    private SizeMode _sizeMode = SizeMode.Medium;
-    private static readonly List<SizeMode> _sizeModes = Enum.GetValues<SizeMode>().ToList();
-
-    private string FormatSizeText(SizeMode size) => size switch
-    {
-        SizeMode.Small => "Klein",
-        SizeMode.Medium => "Mittel",
-        SizeMode.Large => "Groß",
-        _ => size.ToString()
-    };
-
-    private void OnSizeChange(DropDownButtonItemClickEventArgs args)
-    {
-        _sizeMode = Enum.Parse<SizeMode>(args.ItemInfo.Id);
-    }
-
     protected override async Task OnInitializedAsync()
     {
-        columnLookup = columnDefinitions.ToDictionary(c => c.FieldName, StringComparer.OrdinalIgnoreCase);
+        await InitializeBandLayoutAsync();
-        layoutUser = await BandLayoutService.EnsureLayoutUserAsync();
-        bandLayout = await BandLayoutService.LoadBandLayoutAsync(LayoutType, LayoutKey, layoutUser, columnLookup);
-        columnBandAssignments = BandLayoutService.BuildAssignmentsFromLayout(bandLayout);
-        ApplyColumnLayoutFromStorage();
-        _sizeMode = bandLayout.SizeMode;
-        UpdateBandOptions();
         await LoadCatalogs();
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
-        if (!gridLayoutApplied && gridRef != null && bandLayout.GridLayout != null)
+        await ApplyGridLayoutAfterRenderAsync();
-        {
-            gridRef.LoadLayout(bandLayout.GridLayout);
-            gridLayoutApplied = true;
-            await InvokeAsync(StateHasChanged);
-        }
     }
 
     private async Task LoadCatalogs()
@@ -238,185 +202,7 @@ else
         }
     }
 
-    private async Task SaveLayoutAsync()
+    protected override void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-            return;
-
-        try
-        {
-            CaptureColumnLayoutFromGrid();
-            await BandLayoutService.SaveBandLayoutAsync(LayoutType, LayoutKey, layoutUser, bandLayout);
-            infoMessage = "Layout gespeichert.";
-            errorMessage = null;
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Layout konnte nicht gespeichert werden: {ex.Message}";
-        }
-    }
-
-    private 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;
-
-        if (gridRef != null)
-            gridRef.LoadLayout(new GridPersistentLayout());
-        gridLayoutApplied = false;
-
-        infoMessage = "Layout zurückgesetzt.";
-        errorMessage = null;
-    }
-
-    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);
-    }
-
-    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);
-        foreach (var key in columnBandAssignments.Where(p => p.Value == band.Id).Select(p => p.Key).ToList())
-            columnBandAssignments.Remove(key);
-        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)
-        => columnBandAssignments.TryGetValue(fieldName, out var bandId) ? bandId : string.Empty;
-
-    private 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();
-        }
-        StateHasChanged();
-    }
-
-    private void UpdateBandOptions()
-    {
-        bandOptions = new List<BandOption> { new() { Id = string.Empty, Caption = "Ohne Band" } };
-        bandOptions.AddRange(bandLayout.Bands.Select(b => new BandOption { Id = b.Id, Caption = b.Caption }));
-    }
-
-    private RenderFragment RenderColumns() => builder =>
-    {
-        var seq = 0;
-        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();
-        }
-    };
-
-    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);
-        builder.CloseComponent();
-    }
-
-    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;
 
@@ -434,8 +220,6 @@ else
         }
     }
 
-    private void SetPopupHeaderText(bool isNew) => popupHeaderText = isNew ? "Neu" : "Edit";
-
     private void OnCustomizeEditModel(GridCustomizeEditModelEventArgs e)
     {
         popupHeaderText = e.IsNew ? "Neu" : "Edit";

DbFirst.BlazorWebApp/Components/MassDataGrid.razor

@@ -1,5 +1,5 @@
-@inject MassDataApiClient Api
+@inherits BandGridBase<MassDataReadDto>
-@inject BandLayoutService BandLayoutService
+@inject IMassDataApiClient Api
 
 @if (!string.IsNullOrWhiteSpace(errorMessage))
 {
@@ -25,44 +25,17 @@ else if (items.Count == 0)
 else
 {
     
-    <div class="band-editor">
+    <BandEditor Bands="@bandLayout.Bands"
-        <button class="band-editor-toggle" @onclick="() => bandEditorExpanded = !bandEditorExpanded">
+                BandOptions="@bandOptions"
-            <span class="band-editor-toggle-icon @(bandEditorExpanded ? "expanded" : "")">&#9658;</span>
+                Columns="@ColumnDefinitions"
-            <span>Layout</span>
+                GetColumnBand="GetColumnBand"
-        </button>
+                CanSave="@CanSaveBandLayout"
-        @if (bandEditorExpanded)
+                OnAddBand="AddBand"
-        {
+                OnSaveLayout="SaveLayoutWithFeedbackAsync"
-            <div class="band-editor-body">
+                OnResetLayout="ResetLayoutWithFeedbackAsync"
-                <div class="band-controls">
+                OnRemoveBand="RemoveBand"
-                    <DxButton Text="Band hinzufügen" Click="AddBand" />
+                OnBandCaptionChanged="@(args => UpdateBandCaption(args.Band, args.Value))"
-                    <DxButton Text="Layout speichern" Click="SaveLayoutAsync" Enabled="@CanSaveBandLayout" />
+                OnColumnBandChanged="@(args => UpdateColumnBand(args.FieldName, args.BandId))" />
-                    <DxButton Text="Layout zurücksetzen" Click="ResetLayoutAsync" />
-                </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>
 
     <div class="mb-3 page-size-selector">
         <span class="page-size-label">Datensätze je Seite:</span>
@@ -78,6 +51,7 @@ else
 
     <div class="grid-section">
         <DxGrid Data="@items"
+                ColumnChooserButtonDisplayMode="GridColumnChooserButtonDisplayMode.Always"
                 TItem="MassDataReadDto"
                 KeyFieldName="@nameof(MassDataReadDto.Id)"
                 SizeMode="@_sizeMode"
@@ -98,9 +72,42 @@ else
                 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)"
@@ -168,38 +175,24 @@ else
 
 @code {
     private List<MassDataReadDto> items = new();
-    private bool isLoading;
-    private bool hasLoaded;
-    private string? errorMessage;
-    private string? infoMessage;
     private int pageIndex;
     private int pageCount = 1;
     private int? pageSize = 100;
-    private string popupHeaderText = "Edit";
-    private EditContext? editContext;
-    private ValidationMessageStore? validationMessageStore;
-    private IGrid? gridRef;
     private int? focusedRowKey;
-    private const string LayoutType = "GRID_BANDS";
-    private const string LayoutKey = "MassDataGrid";
-    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 bool gridLayoutApplied;
-    private bool bandEditorExpanded;
 
-    private List<ColumnDefinition> columnDefinitions = new()
+    protected override string LayoutKey => "MassDataGrid";
-    {
+    protected override bool ShowCommandColumn => false;
-        new() { FieldName = nameof(MassDataReadDto.Id), Caption = "Id", Width = "90px", ReadOnly = true, FilterType = ColumnFilterType.Text },
+
-        new() { FieldName = nameof(MassDataReadDto.CustomerName), Caption = "CustomerName", FilterType = ColumnFilterType.Text },
+    protected override List<ColumnDefinition> ColumnDefinitions { get; } = new()
-        new() { FieldName = nameof(MassDataReadDto.Amount), Caption = "Amount", DisplayFormat = "c2", FilterType = ColumnFilterType.Text },
+{
-        new() { FieldName = nameof(MassDataReadDto.Category), Caption = "Category", ReadOnly = true, FilterType = ColumnFilterType.Text },
+    new() { FieldName = nameof(MassDataReadDto.Id),           Caption = "Id",           Width = "90px", ReadOnly = true, FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(MassDataReadDto.StatusFlag), Caption = "Status", ReadOnly = true, FilterType = ColumnFilterType.Bool },
+    new() { FieldName = nameof(MassDataReadDto.CustomerName), Caption = "CustomerName",                 FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(MassDataReadDto.AddedWhen), Caption = "Added", ReadOnly = true, FilterType = ColumnFilterType.Date },
+    new() { FieldName = nameof(MassDataReadDto.Amount),       Caption = "Amount",       DisplayFormat = "c2", FilterType = ColumnFilterType.Text },
-        new() { FieldName = nameof(MassDataReadDto.ChangedWhen), Caption = "Changed", ReadOnly = true, FilterType = ColumnFilterType.Date }
+    new() { FieldName = nameof(MassDataReadDto.Category),     Caption = "Category",     ReadOnly = true, FilterType = ColumnFilterType.Text },
-    };
+    new() { FieldName = nameof(MassDataReadDto.StatusFlag),   Caption = "Status",       ReadOnly = true, FilterType = ColumnFilterType.Bool },
+    new() { FieldName = nameof(MassDataReadDto.AddedWhen),    Caption = "Added",        ReadOnly = true, FilterType = ColumnFilterType.Date },
+    new() { FieldName = nameof(MassDataReadDto.ChangedWhen),  Caption = "Changed",      ReadOnly = true, FilterType = ColumnFilterType.Date }
+};
 
     private readonly List<PageSizeOption> pageSizeOptions = new()
     {
@@ -215,44 +208,15 @@ else
         new() { Value = 0, Text = "PRMassdata_UpsertByCustomerName" }
     };
 
-    private bool CanSaveBandLayout => !string.IsNullOrWhiteSpace(layoutUser);
-
-    private SizeMode _sizeMode = SizeMode.Medium;
-    private static readonly List<SizeMode> _sizeModes = Enum.GetValues<SizeMode>().ToList();
-
-    private string FormatSizeText(SizeMode size) => size switch
-    {
-        SizeMode.Small => "Klein",
-        SizeMode.Medium => "Mittel",
-        SizeMode.Large => "Groß",
-        _ => size.ToString()
-    };
-
-    private void OnSizeChange(DropDownButtonItemClickEventArgs args)
-    {
-        _sizeMode = Enum.Parse<SizeMode>(args.ItemInfo.Id);
-    }
-
     protected override async Task OnInitializedAsync()
     {
-        columnLookup = columnDefinitions.ToDictionary(c => c.FieldName, StringComparer.OrdinalIgnoreCase);
+        await InitializeBandLayoutAsync();
-        layoutUser = await BandLayoutService.EnsureLayoutUserAsync();
-        bandLayout = await BandLayoutService.LoadBandLayoutAsync(LayoutType, LayoutKey, layoutUser, columnLookup);
-        columnBandAssignments = BandLayoutService.BuildAssignmentsFromLayout(bandLayout);
-        ApplyColumnLayoutFromStorage();
-        _sizeMode = bandLayout.SizeMode;
-        UpdateBandOptions();
         await LoadPage(0);
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
-        if (!gridLayoutApplied && gridRef != null && bandLayout.GridLayout != null)
+        await ApplyGridLayoutAfterRenderAsync();
-        {
-            gridRef.LoadLayout(bandLayout.GridLayout);
-            gridLayoutApplied = true;
-            await InvokeAsync(StateHasChanged);
-        }
     }
 
     private async Task LoadPage(int page)
@@ -288,171 +252,7 @@ else
         await LoadPage(0);
     }
 
-    private async Task SaveLayoutAsync()
+    protected override void OnEditFieldChanged(object? sender, FieldChangedEventArgs e)
-    {
-        if (string.IsNullOrWhiteSpace(layoutUser))
-            return;
-        try
-        {
-            CaptureColumnLayoutFromGrid();
-            await BandLayoutService.SaveBandLayoutAsync(LayoutType, LayoutKey, layoutUser, bandLayout);
-            infoMessage = "Layout gespeichert.";
-            errorMessage = null;
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Layout konnte nicht gespeichert werden: {ex.Message}";
-        }
-    }
-
-    private 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;
-        if (gridRef != null)
-            gridRef.LoadLayout(new GridPersistentLayout());
-        gridLayoutApplied = false;
-        infoMessage = "Layout zurückgesetzt.";
-        errorMessage = null;
-    }
-
-    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);
-    }
-
-    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);
-        foreach (var key in columnBandAssignments.Where(p => p.Value == band.Id).Select(p => p.Key).ToList())
-            columnBandAssignments.Remove(key);
-        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)
-        => columnBandAssignments.TryGetValue(fieldName, out var bandId) ? bandId : string.Empty;
-
-    private 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();
-        }
-        StateHasChanged();
-    }
-
-    private void UpdateBandOptions()
-    {
-        bandOptions = new List<BandOption> { new() { Id = string.Empty, Caption = "Ohne Band" } };
-        bandOptions.AddRange(bandLayout.Bands.Select(b => new BandOption { Id = b.Id, Caption = b.Caption }));
-    }
-
-    private RenderFragment RenderColumns() => builder =>
-    {
-        var seq = 0;
-        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();
-        }
-    };
-
-    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);
-        builder.CloseComponent();
-    }
-
-    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(MassDataEditModel.UpdateProcedure))
@@ -468,9 +268,7 @@ else
         }
     }
 
-    private void SetPopupHeaderText(bool isNew) => popupHeaderText = isNew ? "Neu" : "Edit";
+    private void OnCustomizeEditModel(GridCustomizeEditModelEventArgs e)
-
-    private async Task OnCustomizeEditModel(GridCustomizeEditModelEventArgs e)
     {
         if (e.IsNew)
         {
@@ -523,18 +321,17 @@ else
             Category = editModel.Category,
             StatusFlag = editModel.StatusFlag
         };
-        try
+
+        var result = await Api.UpsertAsync(dto);
+        if (!result.Success)
         {
-            var saved = await Api.UpsertAsync(dto);
+            errorMessage = result.Error ?? "Speichern fehlgeschlagen.";
-            infoMessage = editModel.IsNew ? "MassData angelegt." : "MassData aktualisiert.";
-            focusedRowKey = saved.Id;
-            await LoadPage(pageIndex);
-        }
-        catch (Exception ex)
-        {
-            errorMessage = $"Fehler beim Speichern: {ex.Message}";
             e.Cancel = true;
+            return;
         }
+        infoMessage = editModel.IsNew ? "MassData angelegt." : "MassData aktualisiert.";
+        focusedRowKey = result.Value?.Id;
+        await LoadPage(pageIndex);
     }
 
     private void AddValidationError(MassDataEditModel editModel, string fieldName, string message)

DbFirst.BlazorWebApp/Components/Pages/Dashboard.razor

@@ -1,9 +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
+@inject IDashboardApiClient DashboardApi
 
 <PageTitle>Dashboards</PageTitle>
 
@@ -45,12 +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 DashboardEndpoint => $"{AppSettingsOptions.Value.ApiBaseUrl.TrimEnd('/')}/api/dashboard";
-    private string HubEndpoint => $"{Configuration["ApiBaseUrl"]?.TrimEnd('/')}/hubs/dashboards";
+    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)
@@ -67,11 +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;

DbFirst.BlazorWebApp/Components/Pages/Home.razor

@@ -31,8 +31,8 @@
 
     public class CarouselData
     {
-        public string Source { get; set; }
+        public string Source { get; set; } = string.Empty;
-        public string AlternateText { get; set; }
+        public string AlternateText { get; set; } = string.Empty;
 
         public CarouselData(string source, string alt)
         {

DbFirst.BlazorWebApp/Components/_Imports.razor

@@ -18,3 +18,4 @@
 @using DevExpress.DashboardBlazor
 @using DevExpress.DashboardWeb
 @using DevExpress.Data.Filtering
+@using Microsoft.Extensions.Options

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);
+}

DbFirst.BlazorWebApp/Models/Grid/BandLayoutModels.cs

@@ -4,8 +4,8 @@ namespace DbFirst.BlazorWebApp.Models.Grid
 {
     public class BandLayout
     {
-        public List<BandDefinition> Bands { get; set; } = new();
+        public List<BandDefinition> Bands { get; set; } = [];
-        public List<string> ColumnOrder { get; set; } = new();
+        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;
@@ -15,7 +15,7 @@ namespace DbFirst.BlazorWebApp.Models.Grid
     {
         public string Id { get; set; } = string.Empty;
         public string Caption { get; set; } = string.Empty;
-        public List<string> Columns { get; set; } = new();
+        public List<string> Columns { get; set; } = [];
     }
 
     public class BandOption

DbFirst.BlazorWebApp/Program.cs

@@ -1,3 +1,4 @@
+using DbFirst.BlazorWebApp;
 using DbFirst.BlazorWebApp.Components;
 using DbFirst.BlazorWebApp.Services;
 using DevExpress.Blazor;
@@ -13,33 +14,18 @@ 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.

DbFirst.BlazorWebApp/Services/ApiClientHelper.cs

@@ -0,0 +1,60 @@
+using System.Net;
+using System.Net.Http.Json;
+
+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);
+    }
+}

DbFirst.BlazorWebApp/Services/BandLayoutService.cs

@@ -5,20 +5,26 @@ using System.Text.Json;
 
 namespace DbFirst.BlazorWebApp.Services
 {
-    public class BandLayoutService(LayoutApiClient layoutApi, IJSRuntime jsRuntime)
+    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);
             }
-            return layoutUser;
+
+            _cachedLayoutUser = layoutUser;
+            return _cachedLayoutUser;
         }
 
         public async Task<BandLayout> LoadBandLayoutAsync(
@@ -82,9 +88,9 @@ namespace DbFirst.BlazorWebApp.Services
             Dictionary<string, ColumnDefinition> columnLookup)
         {
             layout ??= new BandLayout();
-            layout.Bands ??= new List<BandDefinition>();
+            layout.Bands ??= [];
-            layout.ColumnOrder ??= new List<string>();
+            layout.ColumnOrder ??= [];
-            layout.ColumnWidths ??= new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
+            layout.ColumnWidths ??= [];
 
             foreach (var band in layout.Bands)
             {

DbFirst.BlazorWebApp/Services/CatalogApiClient.cs

@@ -4,7 +4,7 @@ using DbFirst.BlazorWebApp.Models;
 
 namespace DbFirst.BlazorWebApp.Services;
 
-public class CatalogApiClient
+public class CatalogApiClient : ICatalogApiClient
 {
     private readonly HttpClient _httpClient;
     private const string Endpoint = "api/catalogs";
@@ -14,123 +14,51 @@ 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);
+        var result = await _httpClient.GetFromJsonAsync<List<CatalogReadDto>>(Endpoint, ct);
-        return result ?? new List<CatalogReadDto>();
+        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; }
 }

DbFirst.BlazorWebApp/Services/DashboardApiClient.cs

@@ -3,7 +3,7 @@ using DbFirst.BlazorWebApp.Models;
 
 namespace DbFirst.BlazorWebApp.Services;
 
-public class DashboardApiClient
+public class DashboardApiClient : IDashboardApiClient
 {
     private readonly HttpClient _httpClient;
     private const string Endpoint = "api/dashboard/dashboards";
@@ -13,9 +13,9 @@ 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);
+        var result = await _httpClient.GetFromJsonAsync<List<DashboardInfoDto>>(Endpoint, ct);
-        return result ?? new List<DashboardInfoDto>();
+        return result ?? [];
     }
 }

DbFirst.BlazorWebApp/Services/ICatalogApiClient.cs

@@ -0,0 +1,12 @@
+using DbFirst.BlazorWebApp.Models;
+
+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);
+}

DbFirst.BlazorWebApp/Services/IDashboardApiClient.cs

@@ -0,0 +1,9 @@
+using DbFirst.BlazorWebApp.Models;
+
+namespace DbFirst.BlazorWebApp.Services
+{
+    public interface IDashboardApiClient
+    {
+        Task<List<DashboardInfoDto>> GetAllAsync(CancellationToken ct = default);
+    }
+}

DbFirst.BlazorWebApp/Services/ILayoutApiClient.cs

@@ -0,0 +1,11 @@
+using DbFirst.BlazorWebApp.Models;
+
+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);
+    }
+}

DbFirst.BlazorWebApp/Services/IMassDataApiClient.cs

@@ -0,0 +1,12 @@
+using DbFirst.BlazorWebApp.Models;
+
+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);
+    }
+}

DbFirst.BlazorWebApp/Services/LayoutApiClient.cs

@@ -3,7 +3,7 @@ using DbFirst.BlazorWebApp.Models;
 
 namespace DbFirst.BlazorWebApp.Services;
 
-public class LayoutApiClient
+public class LayoutApiClient : ILayoutApiClient
 {
     private readonly HttpClient _httpClient;
     private const string Endpoint = "api/layouts";
@@ -13,10 +13,10 @@ 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 +26,12 @@ 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 +39,10 @@ public class LayoutApiClient
         return payload ?? dto;
     }
 
-    private static async Task<string> ReadErrorAsync(HttpResponseMessage response)
+    public async Task DeleteAsync(string layoutType, string layoutKey, string userName, CancellationToken ct = default)
-    {
-        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);
+        var response = await _httpClient.DeleteAsync(url, ct);
         if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
         {
             return;

DbFirst.BlazorWebApp/Services/MassDataApiClient.cs

@@ -3,7 +3,7 @@ using DbFirst.BlazorWebApp.Models;
 
 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);
+        var result = await _httpClient.GetFromJsonAsync<List<MassDataReadDto>>(url, ct);
-        return result ?? new List<MassDataReadDto>();
+        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($"{Endpoint}/upsert", dto);
+        var response = await _httpClient.PostAsJsonAsync($"{Endpoint}/upsert", dto, ct);
-        response.EnsureSuccessStatusCode();
+        if (response.IsSuccessStatusCode)
-        var payload = await response.Content.ReadFromJsonAsync<MassDataReadDto>();
+        {
-        return payload ?? new MassDataReadDto();
+            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;

DbFirst.Infrastructure/DependencyInjection.cs

@@ -1,3 +1,5 @@
+using DbFirst.Application.Repositories;
+using DbFirst.Infrastructure.Repositories;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -15,6 +17,10 @@ public static class DependencyInjection
         services.AddDbContext<MassDataDbContext>(options =>
             options.UseSqlServer(configuration.GetConnectionString("MassDataConnection")));
 
+        services.AddScoped<ICatalogRepository, CatalogRepository>();
+        services.AddScoped<IMassDataRepository, MassDataRepository>();
+        services.AddScoped<ILayoutRepository, LayoutRepository>();
+
         return services;
     }
 }

DbFirst.Infrastructure/Repositories/LayoutRepository.cs

@@ -34,7 +34,7 @@ public class LayoutRepository : ILayoutRepository
                 UserName = userName,
                 LayoutData = layoutData,
                 AddedWho = userName,
-                AddedWhen = DateTime.Now
+                AddedWhen = DateTime.UtcNow
             };
             _db.SmfLayouts.Add(entity);
         }