ComboBox的SelectionChanged事件

一般而言，ComboBox的SelectionChanged事件中都應檢查ComboBox是否被打開，若沒打開則不作任何動作，方法可以參考以下

private void SupplierComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)

        {

            // IsDropDownOpen serves for two purposes here:

            // 1. Close the drop down after the user selected a value (It seems like the drop down would not close if a message box is pop up)

            // 2. Acts as an indicator for this method to prevent recursion when this method rollbacks a data

            if (this.SupplierComboBox.IsDropDownOpen && this.AccessoryGoodsReceive != null && this.AccessoryGoodsReceive.Details != null &&

                this.AccessoryGoodsReceive.Details.Count > 0 && e.RemovedItems.Count >= 1 && e.RemovedItems[0] != null)

            {

                this.SupplierComboBox.IsDropDownOpen = false;

 

                if (MessageBox.Show("Currently mapped APOs will be removed, proceed?", "Change Supplier", MessageBoxButton.OKCancel) == MessageBoxResult.OK)

                {

                    this.AccessoryGoodsReceive.Details.Clear();

                    AvailableAccessoryPurchaseOrderDataGrid.ItemsSource = new ObservableCollection<AccessoryGoodsReceiveDetail>();

                }

                else

                {

                    this.AccessoryGoodsReceive.Supplier = e.RemovedItems[0] as SupplierMaster;

                }

            }

        }