Trying to trigger an event if my cbo box control Is Null or ""

[alsoto]

Hello,



I'm trying to trigger an event if the SSN combo box control in my form Is Null or "". It just won't work.

I have attached an access file with the form and the underlying table which is the record source for the SSN combo box control. To demonstrate my problem, I have a text box which is filled by the after update event of the control with this code:

Private Sub SSN_AfterUpdate()
If Me.SSN = "" Or Null Then
Me.test = "NULL"
Else
Me.test = "NOT NULL"
End If
End Sub

When I choose a SSN from the combo box control, text box test is updated to "NOT NULL". When I clear the combo box, nothing happens. Text box test is not updated with "NULL".

I apologize if this is something obvious, but I have wasted a couple of hours trying to figure it out and I am at my wit's end.

Please help.

Thanks in advance,
Al

[alsoto]

This Worked:

Private Sub SSN_AfterUpdate()

If nz(SSN,"") = "" Then
Me.test = "NULL"
Else
Me.test = "NOT NULL"
End If

End Sub