C# delegate event关系

 

有几篇文章写的蛮好

点击打开链接http://www.tracefact.net/csharp-programming/delegates-and-events-in-csharp.aspx

点击打开链接http://www.cnblogs.com/lin614/archive/2007/01/30/634576.html

 

起因：

发现这个event加不加的无所谓嘛，都可以执行的，后来发现有玄机的，参看上面2篇文章。

//public EventHandler<CarInfoArgs> noticeDelegate;
 public event EventHandler<CarInfoArgs> noticeDelegate;

class Program

    {

        static void Main(string[] args)

        {

            Dealer xiaowang = new Dealer("xiaowang");

            Consumer lilaoban = new Consumer();

            Consumer zhanglaoban = new Consumer();

            xiaowang.noticeDelegate +=new EventHandler<CarInfoArgs>(

                lilaoban.getNotice);

            xiaowang.noticeDelegate += zhanglaoban.getNotice;

            xiaowang.notice("qq");

            xiaowang.noticeDelegate -= zhanglaoban.getNotice;

            xiaowang.notice("handrover");

            //xiaowang.noticeDelegate = null;

            Console.ReadLine();

        }



        static void xiaowang_noticeDelegate(object sender, CarInfoArgs e)

        {

            throw new NotImplementedException();

        }

    }



    class CarInfoArgs :EventArgs{

            public string carinfo { get; set; }

            public CarInfoArgs(string car)

            {

                this.carinfo = car;

            }

        }

        class Dealer { 

            public string name { get; set; }

            public Dealer(string name)

            {

                this.name = name;

            }

            //public EventHandler<CarInfoArgs> noticeDelegate;

            public event EventHandler<CarInfoArgs> noticeDelegate;

            public void notice(string car) {

                if (noticeDelegate != null)

                {

                    noticeDelegate(this, new CarInfoArgs(car));

                }

                

            }

        }



        class Consumer { 

            public void getNotice(object sender, CarInfoArgs e) {

                Console.WriteLine("{0} got notice from {1} on car type : {2}",this.ToString(),((Dealer)sender).name,e.carinfo);

            }

        }