.NET事件机制

1，声明事件 2，声明事件触发后所执行的代理 3，声明触发事件方法 4，订阅事件
实例：制造者与购买者

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EventDemo.NewFolder
{
    public class CarMakerEventArgs : EventArgs
    {
        private readonly string carNumber;
        private readonly string carBrand;
        private readonly string productDate;
        public string CarNumber
        {
            get { return this.carNumber; }
        }
        public string CarBrand
        {
            get { return this.carBrand;}
        }
        public string ProductDate
        {
            get { return this.productDate; }
        }
        public CarMakerEventArgs(string carNumber, string carBrand, string productDate)
        {
            this.carNumber = carNumber;
            this.carBrand = carBrand;
            this.productDate = productDate;
        }
    }
    public class CarMaker
    {
        public delegate void CarMakerEventHandler(object sender,CarMakerEventArgs e);//声明委托代理
        public event CarMakerEventHandler CarMake;//声明事件
        protected virtual void OnCarMaker(CarMakerEventArgs e)//声明触发事件方法
        {
            CarMakerEventHandler handler = CarMake;
            if (handler!=null)
            {
                handler(this, e);
            }
        }
        public void IsSureMake(string carNumber, string carBrand, string productDate)
        {
            Console.WriteLine(productDate+"量产"+carBrand+carNumber+"汽车");
            OnCarMaker(new CarMakerEventArgs(productDate, carBrand, carNumber));
        }
    }
    public class CarBuyer
    {
        private string buyerName;
        public CarBuyer(string buyerName)
        {
            this.buyerName = buyerName;
        }
        public void Buy(object sender,CarMakerEventArgs e)
        {
            Console.WriteLine(this.buyerName+"于"+"2012-12-12购买了于"+e.ProductDate+"生产的"+e.CarBrand+e.CarNumber+"汽车!");
        }
    }
} 

 Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using EventDemo.NewFolder;
namespace EventDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            Demo005();
        }
        static void Demo005()
        {
            CarMaker cm = new CarMaker();
            CarBuyer cb1 = new CarBuyer("B1");
            CarBuyer cb2 = new CarBuyer("B2");
            cm.CarMake += new CarMaker.CarMakerEventHandler(cb1.Buy);
            cm.CarMake += new CarMaker.CarMakerEventHandler(cb2.Buy);
            cm.IsSureMake("Z4","宝马",DateTime.Now.ToString("yyyy-MM-dd"));
            Console.WriteLine("---------------------");
            cm.CarMake -= new CarMaker.CarMakerEventHandler(cb2.Buy);
            cm.IsSureMake("S320", "宝马", DateTime.Now.ToString("yyyy-MM-dd"));
            Console.ReadKey();
        }
    }
}