关于C#-委托和事件研究

      委托和事件这两个概念是完全配合的。委托仅仅是函数指针，那就是说，它能够引用函数，通过传递地址的机制完成。委托是一个类，当你对它实例化时，要提供一个引用函数，将其作为它构造函数的参数。

using System;
class TestClass
{
     static void Main(string[] args)
      {
         EventClass myEventClass = new EventClass();
         myEventClass.CustomEvent += new EventClass.CustomEventHandler(CustomEvent1); // 关联事件句柄;
         myEventClass.CustomEvent += new EventClass.CustomEventHandler(CustomEvent2);
         //这里会将所有关联的函数一直执行
         myEventClass.InvokeEvent();
         //删除一个实践CustomEvent2关联
         myEventClass.CustomEvent -= new EventClass.CustomEventHandler(CustomEvent2);
         myEventClass.InvokeEvent();
         //又增加一个关联
         myEventClass.Load += new EventClass.CustomEventHandler(Load1);
         myEventClass.onLoad();
         Console.Read();
    }

    private static void CustomEvent1(object sender, EventArgs e)
    {
        Console.WriteLine("Fire Event 1");
    }
    private static void CustomEvent2(object sender, EventArgs e)
    {
        Console.WriteLine("Fire Event 2");
    }
    private static void Load1(object sender, EventArgs e)
    {
        Console.WriteLine("Current background color is {0}. Please input:", System.Console.BackgroundColor.ToString());
    }
}

public class EventClass
{
    public delegate void CustomEventHandler(object sender, EventArgs e);//首先定义一个委托类型的对象CustomEventHandle
    //用delegate数据类型声明事件，要用event关键字，这里定义了两个字件;
    //用于建立事件关联
    public event CustomEventHandler CustomEvent;
    //用于建立事件关联
    public event CustomEventHandler Load;
    public void InvokeEvent()
    {
        CustomEvent(this, EventArgs.Empty);
    }
    public void onLoad()
    {
        Console.BackgroundColor = ConsoleColor.Red;
        Load(this, EventArgs.Empty);
        string s = Console.ReadLine();
        if (s != "yuping")
        {
            Console.WriteLine("You must type 'yuping' for change it !");
        }
        else
        {
            Console.BackgroundColor = System.ConsoleColor.Black;
            Console.Clear();
        }

    }
}