Add Checkbox and DateTime Editor for frmEdit, New LookupGrid WIP

EDMI_ClientSuite/UserManager/UserControlAssignment.vb

@@ -182,6 +182,11 @@ Public Class UserControlAssignment
                                 Where oRow.Item(_ParentIdColumn) = _ParentRecordId
                                 Select oRow.Item(_ChildIdColumn)
 
+        If _ChildList Is Nothing Then
+            Exit Sub
+        End If
+
+
         Dim oAssignedChildren As EnumerableRowCollection(Of DataRow) = From oRow In _ChildList.AsEnumerable()
                                                                        Where oAssignedChildIds.Contains(oRow.Item(ClassConstants.ATTRIBUTE_ID_COLUMN))