委托与事件 示例

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Me eventSource = new Me("Learning Hard");

            Friend1 obj1 = new Friend1();
            Friend2 obj2 = new Friend2();

            eventSource.BirthDayEvent += new BirthDayEventHandle(obj1.SendGift);
            eventSource.BirthDayEvent += new BirthDayEventHandle(obj2.Buycake);
            eventSource.TimeUp();
            Console.Read();
         }
    }
     

    public class BirthdayEventArgs : EventArgs
    {
        private readonly string name;
        public string Name
        {
            get { return name; }
        }
        
        public BirthdayEventArgs(string name)
        {
            this.name = name;
        }

    }

    public delegate void BirthDayEventHandle(object sender, BirthdayEventArgs e);

    public class Subject
    {
        public event BirthDayEventHandle BirthDayEvent;

        protected virtual void Notify(BirthdayEventArgs e)
        {
            BirthDayEventHandle temp = Interlocked.CompareExchange(ref BirthDayEvent, null, null);
            if(temp != null)
            {
                temp(this, e);
            }
        }
    }

    public class Me : Subject
    {
        private string name;
        public Me(string name)
        {
            this.name = name;
        }

        public void TimeUp()
        {
            BirthdayEventArgs eventarg = new BirthdayEventArgs(name);
            this.Notify(eventarg);
        }
    }


    // 好友对象
    public class Friend1
    {
        public void SendGift(object sender, BirthdayEventArgs e)
        {
            Console.WriteLine(e.Name + " 生日到了，我要送礼物");
        }
    }
    public class Friend2
    {
        public void Buycake(object sender, BirthdayEventArgs e)
        {
            Console.WriteLine(e.Name + " 生日到了,我要准备买蛋糕");
        }
    }


}