主要成员
 public void AddHandler(object key, Delegate value);//将一个委托添加到集合中，使用key作为标记
 public void AddHandlers(EventHandlerList listToAddFrom);//将一个委托从集合中remove
 public Delegate this[object key] { get; set; }//通过使用事件的key获取事件

　　        System.ComponentModel.EventHandlerList eventHandlerList = new System.ComponentModel.EventHandlerList();

            eventHandlerList.AddHandler("key1",new MyDelete(new Component().SayHello));
            eventHandlerList.AddHandler("key2", new MyDelete(new Component().SayHi));
           
            //eventHandlerList.RemoveHandler("key2",new MyDelete(new Component().SayHi));

          
            MyEventHandler +=(MyDelete)eventHandlerList["key1"];
            MyEventHandler += (MyDelete)eventHandlerList["key2"];
            MyEventHandler();