droplist.Items.Insert(0, new ListItem("",""));

Question

为什么插入不进去啊？运行时跟踪局部变量里面是有的，但显示的时候没有这项

Answer 1

private void OrderList_ItemCreated(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
        {
            if(e.Item.ItemType == ListItemType.Header)
            {
                TableCell tc =  e.Item.Cells[3];
                
                DropDownList ddl = new DropDownList();
                ddl.AutoPostBack = true;
                ddl.DataSource =GetData("SELECT DISTINCT A5 FROM Orders");
                ddl.DataTextField = "A5";
                ddl.DataValueField = "A5";
                ddl.DataBind();                ddl.Items.Insert(0, new ListItem("Vendor",""));                ddl.SelectedIndexChanged +=new EventHandler(ddl_SelectedIndexChanged);                tc.Controls.Add(ddl);
                
                Panel3.Visible=false;
            }        } 
我的代码，是绑定后添加的