Public Event Eingabeprüfung(ByVal Status As Boolean)
 
Private Sub txtNachname_Validating(ByVal sender As System.Object, ByVal e As _
  System.ComponentModel.CancelEventArgs) Handles txtNachname.Validating
'Eingabe prüfen
If Me.txtNachname.Text = Nothing Then
 Me.txtNachname.BackColor = Color.Firebrick
 Me.txtNachname.Focus()
 RaiseEvent Eingabeprüfung(False)
 e.Cancel = True
Else
 Me.txtNachname.BackColor = Nothing
 _bsKundenliste.EndEdit()
 RaiseEvent Eingabeprüfung(True)
End If
End Sub

Private Sub DetailEingabe(ByVal Status As Boolean) Handles _
  MeinKunde.Eingabeprüfung
Me.MyDataGridView.Enabled = Status
End Sub

Private Sub txtNachname_TextChanged(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles txtNachname.TextChanged
 
'Status zurücksetzen
If Not txtNachname.Text = Nothing Then
 Me.txtNachname.BackColor = Nothing
 RaiseEvent Eingabeprüfung(True)
End If
End Sub

Ich verwende Micorsoft Windows 7 (64Bit) und Visual Studio 2005 Professional.