private void Send(object sender, RoutedEventArgs e) { try { Unit unit = unit_combo_box.SelectedItem as Unit; Order order = new Order(unit, GuestRequest, message.Text); Business.AddOrder(order); Business.EditOrder(order, "Sent email"); UiOrders.Add(order); // Update the UI Orders list Frame.Navigate(new EditOrderPage(Business, Frame, order, UiUnits, new List <ObservableCollection <Order> > { UiOrders })); } catch (Exception ex) { MaterialDesignThemes.Wpf.DialogHost.Show(ex, "add_order_error_dialogue_host"); } }