asp.net控制項開發基礎(3)

類型可供選擇的按鈕自訂控制項using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI;
using System.ComponentModel;

namespace ComponentControl
{
    public class Ctrl5:Control,IPostBackEventHandler
    {
        private static readonly object obj = new object();

        [Description("按鈕顯示的類型")]
        public BtnType ButtonType
        {
            get { return ViewState["ButtonType"] == null ? BtnType.Button : (BtnType)ViewState["ButtonType"]; }
            set { ViewState["ButtonType"] = value; }
        }

        //事件
        public virtual event EventHandler Click
        {
            add {
                Events.AddHandler(obj, value);
            }
            remove
            {
                Events.RemoveHandler(obj, value);
            }
        }

        //控制項重寫
        protected override void Render(HtmlTextWriter writer)
        {
            if (ButtonType == BtnType.Button)
                writer.Write("<input type=submit name=" + this.UniqueID + " value=Button />");
            else if (ButtonType == BtnType.LinkButton)
                writer.Write("<a href="+Page.GetPostBackClientHyperlink(this,"")+">Button</a>");
        }

        IPostBackEventHandler 成員#region IPostBackEventHandler 成員

        public void RaisePostBackEvent(string eventArgument)
        {
            EventHandler child = (EventHandler)Events[obj];
            if (child != null)
                child(this, EventArgs.Empty);
        }

        #endregion
    }

    //按鈕類型枚舉
    public enum BtnType
    { 
        Button,
        LinkButton
    }
}