flatten grouped results, add try..catch blocks at crititcal places

Jobs/EDMI/ZUGFeRD/PropertyValues.vb

@@ -1,4 +1,5 @@
 Imports System.Collections.Generic
+Imports System.Linq
 Imports System.Reflection
 Imports System.Text.RegularExpressions
 Imports DigitalData.Modules.Logging
@@ -87,6 +88,38 @@ Public Class PropertyValues
         Return New List(Of Object) From {Obj}
     End Function
 
+    Public Function GetFinalPropValue(List As List(Of Object)) As List(Of Object)
+        Dim oResult As New List(Of Object)
+
+        For Each Item In List
+            Dim oItemValue = DoGetFinalPropValue(Item)
+
+            If Not IsNothing(oItemValue) Then
+                oResult.Add(oItemValue)
+            End If
+        Next
+
+        Return oResult
+    End Function
+
+    Private Function DoGetFinalPropValue(Value As Object) As String
+        If TypeOf Value Is List(Of Object) Then
+            Dim oList = DirectCast(Value, List(Of Object))
+            Dim oCount = oList.Count
+
+            Select Case oCount
+                Case 0
+                    Return Nothing
+                Case Else
+                    Return DoGetFinalPropValue(oList.First())
+            End Select
+
+            Return DoGetFinalPropValue(Value)
+        Else
+            Return Value.ToString
+        End If
+    End Function
+
     Private Function GetIndex(Prop As String) As Integer
         If Regex.IsMatch(Prop, _indexPattern) Then
             Dim oMatch = _indexRegex.Match(Prop)