private void EditStaffel(object sender, RoutedEventArgs e)
        {
            try {
                Staffel Current = (Staffel)cbStaffeln.SelectedItem;

                StaffelEdit Edit = new StaffelEdit((Staffel)Current.Clone());
                if ((bool)Edit.ShowDialog())
                {
                    int Selected = this.cbStaffeln.SelectedIndex;
                    ((ObservableCollection <Staffel>) this.cbStaffeln.ItemsSource).Replace(Current, (Staffel)Edit.Return);
                    this.cbStaffeln.SelectedIndex = Selected;
                }
            }
            catch (Exception ex) {
                MessageBox.Show(ex.Message, "Staffel bearbeiten nicht möglich.");
            }
        }
        private void EditStaffel(object sender, RoutedEventArgs e)
        {
            try {
                Staffel Current = (Staffel)cbStaffeln.SelectedItem;

                StaffelEdit Edit = new StaffelEdit((Staffel)Current.Clone());
                if ((bool)Edit.ShowDialog()) {
                    int Selected = this.cbStaffeln.SelectedIndex;
                    ((ObservableCollection<Staffel>)this.cbStaffeln.ItemsSource).Replace(Current, (Staffel)Edit.Return);
                    this.cbStaffeln.SelectedIndex = Selected;
                }

            }
            catch (Exception ex) {
                MessageBox.Show(ex.Message, "Staffel bearbeiten nicht möglich.");
            }
        }