Function in Before Update Event works but does not prevent moving to After Update 1

[waubain]

Every bottle of research medication has a unique barcode. When checking in a new shipment I am trying to prevent accidentally scanning the same bottle twice. I have an unbound form that adds up to 16 barcode records at a time. Each of the 16 barcode controls are named txtUnitBC1 thru txtUnitBC16. A combobox controls how many of the 16 are visible and added to the record set.

I wrote the below function and entered = NoDuplicateBC() into each of the txtUnitBC Before Update Event. The function works as far as finding a duplicate barcode and alerts the user, but then moves to the After Update event function on handling the barcode rather than remaining on the Active control that caused the problem. I have tries several iterations of the below, but this was the lastest.

I understand how to this in a Sub txtUnitBC1_BeforeUpdate(Cancel As Integer), but I am trying to prevent writing 16 separate sub routines. I did read that Cancel = True is a property of the BeforeUpdate object and will not work elsewhere (a beginners interpretation of what I read). But I am lost on how to do the same in a function outside the BeforeUpdate object.

Any help would be appreciated.

Private Function NoDuplicateBC()
Dim frm As Form
Dim ctrl As Access.Control
Dim strTempBC As String
Dim j As Integer
Dim strUnitBC As String



    Set ctrl = Screen.ActiveControl
    Set frm = Screen.ActiveForm
    strUnitBC = "txtUnitBC"

    strTempBC = ctrl.Value
    
    For j = 1 To Me.cboQtyPackage
    
        If ctrl.Name <> Me.Controls(strUnitBC & j).Name Then
                If strTempBC = Me.Controls(strUnitBC & j).Value Then
                    MsgBox "Duplicate scanned barcode", vbExclamation
                        With Me.Controls(ctrl.Name)
                        .Undo
		      .SelStart = 0
                        .SelLength = Len(ctrl.Name)
                        End With
                        Exit Function
                End If
        End If
    Next j
    
End Function

You don't know what you don't know...

 

[MajP]

add Docmd.cancelevent

http://msdn.microsoft.com/en-us/library/office/ff836964.aspx

 

[waubain]

Thanks MajP, worked perfectly.

You don't know what you don't know...