ASP.NET服务器控件开发

        ASP.NET服务器控件开发，如果要实现的是一个单一的控件，不是组合控件（所谓的组合控件是指由两个以上的基本控件组成的复合控件，下面的链接是一篇园子中的前辈写的复合控件事件处理的Blog，参考价值很高
http://www.cnblogs.com/suiqirui19872005/archive/2007/11/05/949708.html
要继承自CompositeControl类，单一控件、包含可视界面的，继承自WebControl类，不需要界面的，例如sqldatasource，继承自Control类）
        在单一控件中，button类型的控件，需要回发的是事件，要实现IPostBackEventHandler接口，实现一个方法   public void RaisePostBackEvent(string eventArgument)
        {
            OnClick(new EventArgs());
        }
；text类型的控件，需要回发的是change事件，需要处理回发的数据，要实现IPostBackDataHandler接口，实现两个方法 public bool LoadPostData(string postDataKey, System.Collections.Specialized.NameValueCollection postCollection)
        {
            string presentValue = Text;
            string postValue = postCollection[postDataKey];
            if (presentValue == null || !presentValue.Equals(postValue))
            {
                Text = postValue;
                return true;
            }
            return false;
        }
        public virtual void RaisePostDataChangedEvent()
        {
            OnTextChanged(new EventArgs());
        }
        

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 ServerControl1
{
    
    [DefaultEvent("Click"),
    DefaultProperty("Text")]
    [ToolboxData("<{0}:WebCustomControl1 runat=server></{0}:WebCustomControl1>")]
    public class WebCustomControl1 : WebControl,IPostBackEventHandler,IPostBackDataHandler
    {
        public static readonly object ClickEvent = new object();
        public event EventHandler Click
        {
            add
            {
                this.Events.AddHandler(ClickEvent, value);
            }
            remove
            {
                this.Events.RemoveHandler(ClickEvent, value);
            }
        }
        [Bindable(true)]
        public virtual string Text
        {
            get
            {
                string s = (string)ViewState["Text"];
                return ((s == null) ? string.Empty : s);
            }
            set
            {
                ViewState["Text"] = value;
            }
        }
        protected override HtmlTextWriterTag TagKey
        {
            get
            {
                return HtmlTextWriterTag.Input;
            }
        }
        protected override void AddAttributesToRender(HtmlTextWriter writer)
        {
            base.AddAttributesToRender(writer);
            writer.AddAttribute("Name", this.UniqueID);
            //输出控件为提交按钮控件
            //writer.AddAttribute("Type", "Submit");
            //输出控件为输入控件
            writer.AddAttribute("Type", "Text");
            writer.AddAttribute(HtmlTextWriterAttribute.Value, this.Text);
        }
        protected virtual void OnClick(EventArgs e)
        {
            EventHandler clickEventDel = Events[ClickEvent] as EventHandler;
            if (clickEventDel != null)
            {
                clickEventDel(this, e);
            }
        }
        public void RaisePostBackEvent(string eventArgument)
        {
            OnClick(new EventArgs());
        }
        protected override void Render(HtmlTextWriter writer)
        {
            if (Page != null)
            {
                Page.VerifyRenderingInServerForm(this);
            }
            base.Render(writer);
        }
        public bool LoadPostData(string postDataKey, System.Collections.Specialized.NameValueCollection postCollection)
        {
            string presentValue = Text;
            string postValue = postCollection[postDataKey];
            if (presentValue == null || !presentValue.Equals(postValue))
            {
                Text = postValue;
                return true;
            }
            return false;
        }
        public virtual void RaisePostDataChangedEvent()
        {
            OnTextChanged(new EventArgs());
        }
        public event EventHandler TextChanged;
        protected virtual void OnTextChanged(EventArgs e)
        {
            if (TextChanged != null)
            {
                TextChanged(this, e);
            }
        }
    }
}