C# Winform 事件处理程序

Question

我的类中有 2 个构造函数：

public partial class Fiche_Ordre : Le_MainForm
    {
         public Fiche_Ordre()
              {
                  InitializeComponent();           
                  Constuct_Page();            
              }
              public Fiche_Ordre(string OrderID): this()
              {

                    Pers_Ordre oPersOrdr = oOrder_BL.Get_OrdreOne_BL(ClientID, Convert.ToInt32(OrderID), false);
                textEdit_RefExpred.Text = oPersOrdr.RefExpd;
                lookUpEdit_Agence.EditValue = oPersOrdr.Agence;
                lookUpEdit_Transport.EditValue = oPersOrdr.Transporteur;
                lookUpEdit_Dest.EditValue = oPersOrdr.DestId;
    ..................
              }

              public void Constuct_Page()
              {
                  try
                  {
                      ClientID = Program.Le_ClientID;
                      ....
              #region LookUpEdidt Destinataire
                   lookUpEdit_Dest.Properties.DataSource = Auxiliaire_BL.FillCombo_BL(false, ClientID).Tables["ComboFill"];
                   lookUpEdit_Dest.Properties.ValueMember = "CODE_DEST";
                   lookUpEdit_Dest.Properties.DisplayMember = "CODE_DEST";
                   LookUpColumnInfoCollection coll_Dest = lookUpEdit_Dest.Properties.Columns;
                   // A column to display the ProductID field's values.
                   coll_Dest.Add(new LookUpColumnInfo("CODE_DEST", 0, "Code Destinataire"));
                   // A column to display the ProductName field's values.
                   coll_Dest.Add(new LookUpColumnInfo("RS_NOM", 0, "Raison Social"));
                   //  Set column widths according to their contents and resize the popup, if required.   
                   lookUpEdit_Dest.Properties.BestFitMode = BestFitMode.BestFitResizePopup;
                   // Enable auto completion search mode.
                   lookUpEdit_Dest.Properties.SearchMode = SearchMode.AutoComplete;
                   // Specify the column against which to perform the search.
                   lookUpEdit_Dest.Properties.AutoSearchColumnIndex = 1;
                   lookUpEdit_Dest.EditValueChanged += new EventHandler(lookUpEdit_Dest_EditValueChanged);
              #endregion
        ...
        }

这很奇怪，因为当我使用public Fiche_Ordre()时，它不会触发new EventHandler(lookUpEdit_Dest_EditValueChanged);;但是当我使用public Fiche_Ordre(string OrderID)时，它确实会触发事件处理程序。

这正常吗？

它从主窗体调用的第一个构造器

 public partial class Le_MainForm : DevExpress.XtraEditors.XtraForm
    {
        public Le_MainForm()
        { 
            InitializeComponent();
            this.Name = "MainUSER";
            if (Program.IsFA) barButtonItem_OrdList.Visibility = DevExpress.XtraBars.BarItemVisibility.Never;

        }
 private void barButtonItem_CreatOrdreAller_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            Close_AllForm();
            Program.AllerRetour = "Ordre Aller";
            Fiche_Ordre f_Fiche = new Fiche_Ordre();
            f_Fiche.Show();
        }

第二个构造函数我称之为

public partial class Liste_Ordres : Le_MainForm
    {
     private void Liste_DobleClic(object sender, EventArgs e)
            {
                try
                {
                    Program.OrderId = gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString();
                    this.Hide();
                    Fiche_Ordre f_Fiche = new Fiche_Ordre(gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString());
                    f_Fiche.Show();
                }
                catch (Exception excThrown)
                {
                    MessageBox.Show(excThrown.Message);
                }
            }

提前谢谢你。

PS：第一个构造函数只是创建新的空白页，第二个构造函数是创建 NOT NEW（编辑页面），所以我传递了 id 并填充了所有控件（文本框、备忘录等......

Answer 1

EditValueChanged句柄连接在Constuct_Page的最后一行。因此，它仅在Constuct_Page之后触发更改。代码的..................部分是否更改？这听起来确实像是一个过于简化的猜测，但无论如何都值得仔细检查......

此外，我可以建议你另一个改进：

public Fiche_Ordre(string OrderID) : this.Fiche_Ordre()
{
  // invokes the other constructor first, so they're guaranteed
  // do be equivalent in the first part
  Pers_Ordre oPersOrdr = oOrder_BL.Get_OrdreOne_BL(ClientID,
    Convert.ToInt32(OrderID), false);
  // ...
}

Answer 2

当你想要绑定事件处理程序时，放置断点并查看lookUpEdit_Dest，我认为这个 var 不初始化，所以你需要将初始化从第二个构造函数添加到第一个。

Answer 3

改为创建Constuct_Page（）; 只需输入 Form_Load（）