C# event入门案例

C#中事件是一种特殊的委托

class Publisher //出版社
    {
        public delegate void Publish();//声明事件所需的代理
        public event Publish OnPublish;//事件的声明
        public void issue()//触发事件
        {
            if (OnPublish != null)
            {
                Console.WriteLine("发行刊物");
                OnPublish();
            }
        }
        
    }
    class Subscriber//订阅者
    {
        public void Receive()//在事件订阅者中定义事件处理程序
        {
            Console.WriteLine("订阅者已经收到刊物");
        }
    }
    class Story
    {
        static void Main()
        {
            Publisher Pub = new Publisher();
            Subscriber zs = new Subscriber();
            Pub.OnPublish+=new Publisher.Publish(zs.Receive);//向事件发行者订阅一个事件
            Pub.issue();//触发事件
        }
    }

 

例子二:

class Publisher//出版社
    {
        public delegate void PubComputer(string magazineName);//声明事件所需的代理
        public delegate void PubLift(string magazineName);
        public event PubComputer OnPubComputer;//事件的声明
        public event PubLift OnPubLife;
        public void issueComputer()//触发事件的方法
        {
            if (OnPubComputer != null)
            {
                Console.WriteLine("发行电脑杂志");
                OnPubComputer("电脑杂志");
            }
        }
        public void issueLife()
        {
            if (OnPubLife != null)
            {
                Console.WriteLine("发行生活杂志");
                OnPubLife("生活杂志");
            }
        }
    }
    class Subscriber//订阅者
    {
        private string name;
        public Subscriber(string name)
        {
            this.name = name;
        }
        public void Receive(string magazineName)//在事件订阅者中定义事件处理程序
        {
            Console.WriteLine(name + "已经收到" + magazineName);
        }
    }
    class Story
    {
        static void Main()
        {
            Publisher Pub = new Publisher();
            Subscriber zs = new Subscriber("张三");
            Pub.OnPubComputer+=new Publisher.PubComputer(zs.Receive);//向事件发行者订阅一个事件
            Subscriber ls = new Subscriber("李四");
            Pub.OnPubComputer += new Publisher.PubLift(ls.Receive);
            Pub.OnPubLife+=new Publisher.PubLift(ls.Receive);
            Pub.issueComputer();//触发事件
            Pub.issueLife();
            Console.WriteLine();
            Console.WriteLine("一年后");
            Pub.OnPubComputer -= new Publisher.PubComputer(ls.Receive);
            Pub.issueComputer();
            Pub.issueLife();
        }
    }