class PubEventArgs : EventArgs    {        private readonly string m_magazineName;        private readonly DateTime m_pubDate;        public PubEventArgs(string magazineName,DateTime pubDate)        {            m_magazineName = magazineName;            m_pubDate = pubDate;        }        public string magazineName        {            get { return m_magazineName; }        }        public DateTime pubDate        {            get { return m_pubDate; }        }    }
    class Publisher  //出版社    {        public delegate void PubComputerEventHandler(object sender, PubEventArgs e);        public delegate void PubLifeEventHandler(object sender, PubEventArgs e);        public event PubComputerEventHandler PubComputer; //电脑杂志事件        public event PubLifeEventHandler PubLife;         //生活杂志事件        protected virtual void OnPubComputer(PubEventArgs e)  //受保护的方法        {            PubComputerEventHandler handler = PubComputer;  //定义临时的委托            if (handler != null)            {                handler(this, e);            }        }        protected virtual void OnPubLife(PubEventArgs e)        {            PubLifeEventHandler handler = PubLife;            if (handler != null)            {                handler(this, e);            }        }        public void issueComputer(string magezineName,DateTime pubDate)        {            Console.WriteLine(pubDate.ToShortDateString() + "发行了" + magezineName);            OnPubComputer(new PubEventArgs(magezineName, pubDate));  //这里调用保护的虚拟方法。        }        public void issueLife(string magezineName, DateTime pubDate)        {            Console.WriteLine(pubDate.ToShortDateString() + "发行了" + magezineName);            OnPubLife(new PubEventArgs(magezineName, pubDate));        }    }    class Pubscriber  //订阅者    {        private string name;        public Pubscriber(string name)        {            this.name = name;        }        public void Receive(object sender, PubEventArgs e)        {            Console.WriteLine("{0} {1} 已经收到{2}", e.pubDate.ToString(), name, e.magazineName);        }    }    class Program    {        static void Main(string[] args)        {            Publisher pub = new Publisher();            Pubscriber zs = new Pubscriber("张三");            pub.PubComputer += new Publisher.PubComputerEventHandler(zs.Receive); //添加事件 用户张三订阅电脑杂志            Pubscriber ls = new Pubscriber("李四");            pub.PubComputer += new Publisher.PubComputerEventHandler(ls.Receive); //添加事件 用户李四订阅电脑杂志            pub.PubLife += new Publisher.PubLifeEventHandler(ls.Receive);     //添加事件 用户李四订阅生活杂志            pub.issueComputer("电脑杂志",Convert.ToDateTime("2014-01-01"));            pub.issueLife("生活杂志",Convert.ToDateTime("2014-01-01"));            Console.WriteLine();            Console.WriteLine("一年后。。。");            pub.PubComputer -= new Publisher.PubComputerEventHandler(ls.Receive);  //移除事件 用户李四取消订阅电脑杂志            pub.issueComputer("电脑杂志", Convert.ToDateTime("2014-02-01"));            pub.issueLife("生活杂志", Convert.ToDateTime("2014-02-01"));            Console.ReadKey();        }    }