DataChanged Property and Validate Event Example

This example illustrates simple data validation. In the Authors table in the Biblio.mdb database, there are two fields: Au_ID and Author. Since the value in Au_ID is used to uniquely identify the author, this value should not change. The example doesn't allow changes to the Au_ID field, which is bound to Text1.

Private Sub Data1_Validate (Action As Integer, Save As Integer)
   If Text1.DataChanged Then   ' Check for change in data.
      MsgBox "You can't change the ID number."
      Text1.DataChanged = False   ' Don't save changed data.
   End If
   ...
End Sub