C#事件——对委托的封装

来源：互联网发布：淘宝美式画编辑：程序博客网时间：2024/05/17 00:16

C#中，正如属性是对成员变量的封装，事件是对委托的封装。

完整的事件流程：

    class Program    {        static void Main(string[] args)        {            EventSender sender = new EventSender();            EventRevicer revicer = new EventRevicer();            sender.myEvent += revicer.Action;                        //invoke the event            sender.Active(new MyEventArgs("C# Event"));        }    }    class MyEventArgs:EventArgs    {        public MyEventArgs(string name)        {            this.name = name;        }        public string name { get; set; }    }    delegate void MyEventHandler(EventSender sender,MyEventArgs e);    class EventSender    {        private MyEventHandler myEventHandler;        public event MyEventHandler myEvent        {            add            {                myEventHandler += value;            }            remove            {                myEventHandler -= value;            }        }        public void Active(MyEventArgs e)        {            Console.WriteLine("I send the notification");            myEventHandler.Invoke(this, e);        }    }    class EventRevicer    {        internal void Action(EventSender sender, MyEventArgs e)        {            Console.WriteLine("I get the notification!");        }    }

简写的事件流程：

    class Program    {        static void Main(string[] args)        {            EventSender sender = new EventSender();            EventRevicer revicer = new EventRevicer();            sender.myEvent += revicer.Action;                        //invoke the event            sender.Active(new MyEventArgs("C# Event"));        }    }    class MyEventArgs : EventArgs    {        public MyEventArgs(string name)        {            this.name = name;        }        public string name { get; set; }    }  class EventSender  {      public event EventHandler myEvent;//the event              public void Active(MyEventArgs e)      {          Console.WriteLine("I send the notification");          myEvent.Invoke(this, e);      }  }  class EventRevicer  {      internal void Action(object sender, EventArgs e)      {          //Type convert          MyEventArgs args = e as MyEventArgs;          Console.WriteLine("I get the notification! args:{0}",args.name);      }  }

注：我们平时经常用的简写流程中省略了事件封装的过程，但实际上C# 语言机制内部是有这个对委托的封装过程的。

0 0