c#事件机制

namespace test
{
class Publisher//出版社
{
public delegate void PubComputer(string magazineName);//声明事件所需的代理
public delegate void PubLife(string magazineName);
public event PubComputer OnPubComputer;//事件的声明 事件的本质是一个委托链
public event PubLife OnPubLife;
public void issueComputer()//触发事件的方法
{
if (OnPubComputer != null){
Console.WriteLine("发行电脑刊物");
OnPubComputer("编程指南");
}
}
public void issueLife()
{
if (OnPubLife!=null) {
Console.WriteLine("发行生活刊物");
OnPubLife("家具");
}
}
}
class Subsriber//订阅者
{
private string name;
public Subsriber(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();
Subsriber zs = new Subsriber("张三");
pub.OnPubComputer += new Publisher.PubComputer(zs.Receive);//向事件发行者订阅一个事件
Subsriber ls = new Subsriber("李四");
pub.OnPubComputer += new Publisher.PubComputer(ls.Receive);
pub.OnPubLife += new Publisher.PubLife(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();//触发事件
pub.issueLife();
}
}

}