C# 事件（event）分析

一直对事件的处理机制不是特别明确，今天看了‘风卷残云后’C#事件解析这篇文章后，模仿了一篇Code之后思路清晰许多，下面是代码：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Text;
 4 
 5 namespace T_Event
 6 {
 7     class Program
 8     {
 9         static void Main(string[] args)
         {
             KeyInputMonitor monitor = new KeyInputMonitor();
 
             EventReceive receive = new EventReceive(monitor);
 
             monitor.run();
         }
     }
 

     //此类用来保存按键信息

        //internal修饰符：使用该修饰符声明的类型或成员只能在同一程集内访问接口的成员

     internal class KeyEventArg:EventArgs
     {
         private char keychar;
 
         public KeyEventArg(char keychar)
         {
             this.keychar = keychar;
         }
 
         public char KeyChar
         {
             get
             {
                 return keychar;
             }
         }
     }
 
     internal class KeyInputMonitor
     { 
         public delegate void keydownhandle(object Sender,KeyEventArg e);
 
         public event keydownhandle Onkeydownhandle;
 
         public void run()
         {
             bool Flag = false;
             do
             {
                 Console.WriteLine("Please Input A Char");
                 string response = Console.ReadLine();
                 char rChar = (response == "") ? ' ' : char.ToUpper(response[0]);
                 switch (rChar)
                 {
                     case 'X':
                         Flag = true;
                         break;
                     default:
                         //实例化一个 KeyEventArg，获取按键信息
                         KeyEventArg keyeventarg = new KeyEventArg(rChar);
                         //触发Onkeydownhandle事件，并交于委托keydownhandle所指定的方法处理
                         Onkeydownhandle(this, keyeventarg);
                         break;
                 }
             } while (!Flag);
         }
     }
 
     internal class EventReceive
     {
         public EventReceive(KeyInputMonitor monitor)
         {
             //程序启动后订阅事件，将委托实例添加到产生事件对象的事件列表中去
             monitor.Onkeydownhandle += new KeyInputMonitor.keydownhandle(this.Echo);
         }
 
             private void Echo(object sender,KeyEventArg e)
             {
                 Console.WriteLine( "Capture key: {0}", e.KeyChar );
                 //看看sender（this）传递的是什么值，原来就是KeyInputMonitor类
                 string strsender = sender.ToString();
                 Console.WriteLine(strsender);
             }
         }

     }

 

注释是按自己的理解写的，如果理解有误欢迎指正