【基础知识】委托与事件

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        /// <summary>
        /// 鼠标左键点击触发事件
        /// </summary>
        /// <param name="sender">指发送通知的对象</param>
        /// <param name="e">包含所有通知接受者包含的附件的信息</param>
        private void button1_Click(object sender, EventArgs e)
        { 
            Cat cat = new Cat("Tom");
            Mouse mouse1 = new Mouse("Jack");
            Mouse mouse2 = new Mouse("Jerry");
            cat.CatShout+=new Cat.CatShoutEventHandler(mouse1.Run);//实例化一个委托，而委托的实例其实就是Mouse的Run方法
            cat.CatShout += new Cat.CatShoutEventHandler(mouse2.Run);
            cat.Shout();//只有当猫叫时才会触发老鼠动作
        }
    }
    //委托是对函数的封装，可以当做给方法的特征指定一个名称。  事件是委托的特殊形式，当发生有意义的事情时，事件对对象处理通知
    /// <summary>
    ///   猫
    /// </summary>
    class Cat
    {
        private string name = "";
        public Cat(string name)
        {
            this.name = name;
        }
        //public delegate void CatShoutEventHandler();//委托
        //public event CatShoutEventHandler CatShout;//事件
        public delegate void CatShoutEventHandler(object sender,CatShoutEventArgs args);//委托
        public event CatShoutEventHandler CatShout;//事件
        public void Shout()
        {
            MessageBox.Show("我是只大花猫，我的名字叫做："+name);
            if (CatShout!=null)
            {
                CatShoutEventArgs e = new CatShoutEventArgs();
                e.Name = this.name;
                CatShout(this,e);
            }
        }
    }
    /// <summary>
    /// 鼠
    /// </summary>
    class Mouse
    {
        private string name="";
        public  Mouse(string name)
        {
            this.name=name;
        }
        //public void Run()
        //{
        //    MessageBox.Show("我是只大老鼠，我的名字叫："+name);
        //}
        public void Run(object sender,CatShoutEventArgs args)
        {
            string message=string.Format("大花猫{0}来了,小老鼠{1}快快跑啊！" ,args.Name,name);
            MessageBox.Show(message);
        }
    }
    /// <summary>
    /// //继承包含事件数据的类的基类
    /// </summary>
    public class CatShoutEventArgs : EventArgs
    {
        private string name = "";
        public String Name
        {
            get { return name; }
            set { name = value; }
        }
    }
}