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);
            }
        }