C# 事件

 

实例1：

using System;
class Publisher//出版社
{
    public delegate void Publish();//事件所需要的委托(注意，声明委托，必须加上括号)
    public event Publish OnPublish;//事件声明
    public void issue()//触发事件的方法
    {
        if (OnPublish != null)
        {
            Console.WriteLine("出版刊物");
            OnPublish();
        }
    }
}
class Subscriber//订阅者
{
    public void Receive()//事件调用方法
    {
        Console.WriteLine("订阅者已经受到刊物!");
    }
}
class Test
{
    public 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
    }
}

 

实例2：

using System;
class Publisher//出版社
{
    public delegate void PubComputer(string magazineName);//事件所需要的委托
    public delegate void PubLife(string magazineName);
    public event PubComputer OnPubComputer;//事件声明
    public event PubLife OnPubLife;
    public void issueComputer()//触发事件的方法
    {
        if (OnPubComputer != null)
        {
            Console.WriteLine("出版<<电脑>>杂志");
            OnPubComputer("电脑杂志");
        }
    }
    public void issueLife()
    {
        if (OnPubLife != null)
        {
            Console.WriteLine("出版<<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)//事件调用方法
    {
        Console.WriteLine(name + "订阅了" + magazineName);
    }
}
class Test
{
    public 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.PubComputer(ls.Receive);//向事件发行者订阅一个事件
        Pub.OnPubLife += new Publisher.PubLife(ls.Receive);//向事件发行者订阅一个事件
        Pub.issueComputer();//触发事件
        Pub.issueLife();//触发事件

        Console.WriteLine();
        Console.WriteLine("一年后");
        Pub.OnPubComputer -= new Publisher.PubComputer(ls.Receive);
        Pub.issueComputer();//触发事件
        Pub.issueLife();//触发事件
    }
}