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