Private Sub txtnummer_KeyPress(Index As Integer, keyAscii As Integer)
 
Select Case Index
   Case 0, 1
   If InStr("1234567890" & Chr$(8), Chr$(keyAscii)) = 0 Then
      keyAscii = 0
   End If
End Select
End Sub

Private Sub txtnummer_KeyPress(KeyAscii As Integer, index As Integer)
 
   Select Case index
   Case 0, 1
   If InStr("1234567890" & Chr$(8), Chr$(KeyAscii)) = 0 Then
      KeyAscii = 0
   End If
 
   End Select
End Sub