Add FIELD Function, fix virtual columns

MultiTool.Shared/Documents/DocumentRow.vb

@@ -65,13 +65,22 @@
             Public Property IsVirtual As Boolean = False
             Public Property SortKey As Integer = 0
 
+            Public Function GetValue(pValueType) As String
+                Select Case pValueType
+                    Case "Original"
+                        Return Original
+                    Case "External"
+                        Return External
+                    Case "Final"
+                        Return Final
+                    Case Else
+                        Return Nothing
+                End Select
+            End Function
+
             Public ReadOnly Property HasError As Boolean
                 Get
                     Return [Error] <> FieldError.None Or (IsRequired And Final = String.Empty)
-
-                    'Return IsRequired = True And (
-                    '    [Error] <> FieldError.None Or Final = String.Empty
-                    ')
                 End Get
             End Property