自定义控件(12)回传事件IPostBackEventHandler

如果一个服务器控件需要支持回传事件，那么它必须要实现IPostBackEventHandler接口

需要实现RaisePostBackEvent(string eventArgument)方法

控件代码

using System;using System.ComponentModel;using System.Web.UI;using System.Web.UI.WebControls;namespace kjlx.BLL.IPostBack{    [ParseChildren(true),            //解析为属性    DefaultEvent("Click")]     public class IPostBackTest2 : WebControl, IPostBackEventHandler    {        //外层DIV        protected override HtmlTextWriterTag TagKey        {            get { return HtmlTextWriterTag.Div; }        }        /// <summary>        /// 给Div添加属性和样式        /// </summary>        /// <param name="writer"></param>        protected override void AddAttributesToRender(HtmlTextWriter writer)        {            base.AddAttributesToRender(writer);  //由于AddAttributeToRender()方法实现了对控件基本属性和样式的支持，所以就算需要重写这个方法，也应当调用base.AddAttributeToRender(),以使自定义控件获得基本的功能。            writer.AddStyleAttribute(HtmlTextWriterStyle.Width, "120px");            writer.AddStyleAttribute(HtmlTextWriterStyle.Height, "35px");            writer.AddStyleAttribute(HtmlTextWriterStyle.BackgroundColor, "#0000aa");            writer.AddStyleAttribute(HtmlTextWriterStyle.Cursor, "pointer");

            //如果是链接,回传事件放在href中,使用GetPostBackClientHyperlink            string upRef = Page.ClientScript.GetPostBackEventReference(this, null);   //创建onclick事件

            writer.AddAttribute(HtmlTextWriterAttribute.Onclick, upRef);              //给onclick事件赋值        }        //Click事件属性        static object ClickHandler=new object();        [Category("Action")]        public event EventHandler Click        {            add            {                Events.AddHandler(ClickHandler,value);            }            remove            {                Events.RemoveHandler(ClickHandler,value);            }                }        /// <summary>        /// 处理网页回传事件        /// 触发控件相应的事件        /// </summary>        /// <param name="eventArgument"></param>        public void RaisePostBackEvent(string eventArgument)        {            EventArgs args=new EventArgs();            if (Events[ClickHandler] != null)            {                (Events[ClickHandler] as EventHandler)(null, args);            }        }    }}

html代码

 <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>    <cc1:IPostBackTest2 ID="IPostBackTest1" runat="server"         onclick="IPostBackTest1_Click" />

后台代码

  protected void IPostBackTest1_Click(object sender, EventArgs e)    {        Label1.Text = "111";    }

显示结果