事件的实现（2）

一个出版社的例子：(发行者和订阅者)

using System;
using System.Collections.Generic;
using System.Text;

namespace eventpro 
{
    class PubEventArgs : EventArgs   //定义一个提供事件数据的类，如果事件不需要传递数据，可以直接使用系统提供的System.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  //事件的发行者
    {
        public delegate void PubComputerEventHandler(object sender,PubEventArgs e); //声明事件所需的代理
        public delegate void PubLifeEventHandler(object sender,PubEventArgs e);
        public event PubComputerEventHandler PubComputer;   //事件声明
        public event PubLifeEventHandler PubLife;

        protected virtual void OnPubComputer(PubEventArgs e) //引发事件类中提供一个受保护的方法，解决可能存在的线程同步问题。以OnEventName进行命名。
        {
            PubComputerEventHandler handler = PubComputer;
            if (handler !=null )
            {
                handler(this,e);
            }
 
        }
        protected virtual void OnPubLife(PubEventArgs e) //引发事件类中提供一个受保护的方法，解决可      能        存在的线程同步问题。以OnEventName进行命名。
        {
            PubLifeEventHandler handler = PubLife;
            if (handler != null)
            {
                handler(this, e);
            }

        }

        public void issueComputer(string magazineName,DateTime pubDate) //触发事件的方法
        {
            Console.WriteLine("发行"+magazineName );
            OnPubComputer(new PubEventArgs (magazineName,pubDate));

        }

        public void issueLife(string magazineName, DateTime pubDate) //触发事件的方法
        {
            Console.WriteLine("发行" + magazineName);
            OnPubLife(new PubEventArgs(magazineName, pubDate));

        }

    }
    class Subscriber //订阅者
    {
        private string name;
        public Subscriber(string name)
        {
            this.name = name;
 
        }
        public void Receive(object sender,PubEventArgs e)//在事件订阅者中定义事件处理程序
        {
            Console.WriteLine(e.pubDate +name +" "+"接收到了"+e.magazineName );
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Publisher Pub = new Publisher();
            Subscriber zs = new Subscriber("张三");
            Pub.PubComputer += new Publisher.PubComputerEventHandler(zs.Receive );//向事件发行者订阅一个事件
            Subscriber ls = new Subscriber("李四");
            Pub.PubComputer += new Publisher.PubComputerEventHandler(ls.Receive );
            Pub.PubLife += new Publisher.PubLifeEventHandler(ls.Receive);

            Pub.issueComputer("电脑杂志",Convert.ToDateTime ("2006-1-1"));
            Pub.issueLife("生活杂志",Convert.ToDateTime ("2006-1-2"));

            Console.WriteLine();
            Console.WriteLine("一年以后");
            Pub.issueComputer("电脑杂志", Convert.ToDateTime("2007-1-1"));
            Pub.issueLife("生活杂志", Convert.ToDateTime("2007-1-2"));

            Console.ReadLine();
        }
    }
}

转载于:https://www.cnblogs.com/michaeltangbin/archive/2007/12/29/1020066.html