// Lager - Verwalten
private void MenuItem_Click_3(object sender, RoutedEventArgs e)
{
//MessageBox.Show("Momentan nicht untertützt", "", MessageBoxButton.OK, MessageBoxImage.Warning);
//return;
StockList window = new StockList(db);
window.Owner = this;
window.dataGrid1.BeginInit();
window.dataGrid1.EndInit();
window.ShowDialog();
}