服务端控件开发 包含处理机制—— 子控件中调用住空间委托的事件实例

using System;using System.Collections.Generic;using System.ComponentModel;using System.Linq;using System.Text;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;namespace ServerControl{    [DefaultProperty("Text")]    [ToolboxData("<{0}:SearchControl runat=server></{0}:SearchControl>")]    public class SearchControl : CompositeControl    {        private Button btnSearch;        private TextBox tbSearchText;        [Category("搜索")]        [DefaultValue("")]        [Description("获取文本的值")]        public string Text        {            get            {                this.EnsureChildControls();                return tbSearchText.Text;            }        }        private static readonly object ButtonSearchClickObject = new object();        public event SearchEventHandler ButtonSearchClick        {            add            {                base.Events.AddHandler(ButtonSearchClickObject, value);            }            remove            {                base.Events.RemoveHandler(ButtonSearchClickObject, value);            }        }        protected override void CreateChildControls()        {            //base.CreateChildControls();            this.Controls.Clear();            btnSearch = new Button();            btnSearch.ID = "btn";            btnSearch.Text = "搜索";            btnSearch.Click += new EventHandler(btnSearch_Click);            tbSearchText = new TextBox();            tbSearchText.ID = "tb";            this.Controls.Add(btnSearch);            this.Controls.Add(tbSearchText);        }        protected virtual void OnButtonSearchClick(SearchEventArgs e)        {             SearchEventHandler ButtonSearchClickHandler=(SearchEventHandler)base.Events[ButtonSearchClickObject];            if (ButtonSearchClickHandler != null)            {                ButtonSearchClickHandler(this, e);            }        }        void btnSearch_Click(object sender, EventArgs e)        {            //throw new NotImplementedException();            SearchEventArgs args = new SearchEventArgs();            args.SearchValue = this.Text;            OnButtonSearchClick(args);        }        protected override void Render(HtmlTextWriter writer)        {            writer.AddAttribute(HtmlTextWriterAttribute.Border, "0px");            writer.AddAttribute(HtmlTextWriterAttribute.Cellpadding, "0px");            writer.AddAttribute(HtmlTextWriterAttribute.Cellspacing, "0px");            writer.RenderBeginTag(HtmlTextWriterTag.Table);            writer.RenderBeginTag(HtmlTextWriterTag.Tr);            writer.RenderBeginTag(HtmlTextWriterTag.Td);            tbSearchText.RenderControl(writer);            writer.RenderEndTag();            writer.RenderBeginTag(HtmlTextWriterTag.Td);            btnSearch.RenderControl(writer);            writer.RenderEndTag();            writer.RenderEndTag();            writer.RenderEndTag();        }        public delegate void SearchEventHandler(object sender, SearchEventArgs e);    }    public class SearchEventArgs : EventArgs    {        public SearchEventArgs() { }        public string SearchValue { get; set; }    }}