I have tried this under BeforeUpdate() and the following and I can't get it
to cancel the event.  I am trying to make the form give an error message if
no name is selected from the list.  Right now, if the EmlpoyeeID field is
left blank the form closes and updates the record.  What am I doing wrong?
----------start code---------------
Private Sub btnOkay_Click()
On Error GoTo Err_btnOkay_Click
       
   If IsNull(Me!EmployeeID) Then
       MsgBox "You must select an employee from the list"
       Me!lblEmployee.ForeColor = 255
       Me!EmployeeID.SetFocus
       Exit Sub
    Else
       Me!lblEmployee.ForeColor = 0
       DoCmd.Close
   End If

           
Exit_btnOkay_Click:
   Exit Sub

Err_btnOkay_Click:
   MsgBox Err.Description
   Resume Exit_btnOkay_Click
   
End Sub
-------------end code----------------