C# 自定义事件

C＃自定义事件和java有所不同，涉及到委托。下面代码包括自定义事件从事件定义到事件触发和执行的全过程。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Timers;
//using System.Timers;namespace EventTest
{
//定义一个委托MessageHandler，可以看作是一个类。
public delegate void MessageHandler(string messageText);
class Connections
{//定义一个事件MessageArrive，是委托的实例
public event MessageHandler MessageArrive;
private Timer pollTimer;
private static Random random = new Random(); public Connections()
{
this.pollTimer = new Timer();
pollTimer.Elapsed += new ElapsedEventHandler(Display);
} public void Connect()
{
pollTimer.Start();
} public void Disconnect()
{
pollTimer.Stop();
} public void Display(object source, ElapsedEventArgs e)
{
Console.WriteLine("New Message Coming");
if (random.Next(9) == 0 && MessageArrive != null)
{
//触发MessageArrive事件
MessageArrive("New Message Arrived, And has been handled successfully");
}
}
static void Main(string[] args)
{
Connections connector = new Connections();
Display displayor = new Display();
//将一个委托实例赋值给事件MessageArrive，参数为方法DisplayMessage,方法的参数要与委托类的参数一致。
connector.MessageArrive += new MessageHandler(displayor.DisplayMessage);
connector.Connect();
Console.ReadKey();
}
} public class Display
{
public void DisplayMessage(string text)
{
Console.WriteLine(text);
}
}
}