LookupGrid: Prevent crash when selectedvalues contains dbnull

Controls.LookupGrid/frmLookupGrid.vb

@@ -70,6 +70,8 @@ Public Class frmLookupGrid
 
         If SelectedValues Is Nothing Then
             SelectedValues = New List(Of String)
+        Else
+            SelectedValues = SelectedValues.Where(Function(v) Not (IsDBNull(v) OrElse String.IsNullOrWhiteSpace(v))).ToList()
         End If
 
         ' Bereits ausgewählte Werte im grid auswählen
@@ -131,14 +133,18 @@ Public Class frmLookupGrid
                     Dim row As DataRow = rowView.Row
                     Dim value = row.Item(_DataColumn)
 
-                    If SelectedValues.Contains(value) Then
-                        If MultiSelect Then
-                            row.Item(0) = True
-                        Else
-                            view.SelectRow(rowHandle)
+                    If Not (IsDBNull(value) OrElse String.IsNullOrWhiteSpace(value)) Then
+                        If SelectedValues.Contains(value) Then
+                            If MultiSelect Then
+                                row.Item(0) = True
+                            Else
+                                view.SelectRow(rowHandle)
+                            End If
                         End If
                     End If
                 End If
+
+
             Next
         End If
     End Sub