什么是委托，事件

之前一直不明白什么是委托与事件，网上的介绍可谓纷繁复杂。晦涩难懂，今天写一个看门大爷都能看懂的委托,事件的实例。话不多说，直接上代码：

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

namespace 委托事件实例
{
    class Program
    {
        static void Main(string[] args)
        {
            A a = new A();//定义首领A
            B b = new B(a);//定义部下B
            C c = new C(a);//定义部下C

            //首领A左手举起
            a.Raise("左");
            //首领A右手举起
            a.Raise("右");
            //首领A摔杯
            a.Fall();

            Console.WriteLine();
            //由于B,C订阅了事件A所以无需任何代码，BC均会按照约定进行动作

        }
    }
    /// <summary>
    /// 首领A举杯委托
    /// </summary>
    /// <param name="hand"></param>
    public delegate void RaiseEventHandler(string hand);
    /// <summary>
    /// 首领A摔杯委托
    /// </summary>
    public delegate void FallEventHandler();

    /// <summary>
    /// 首领A
    /// </summary>
    public class A
    {
        /// <summary>
        /// 首领A举杯事件
        /// </summary>
        public event RaiseEventHandler RaiseEvent;
        /// <summary>
        /// 首领A摔杯事件
        /// </summary>
        public event FallEventHandler FallEvent;
        /// <summary>
        /// 举杯
        /// </summary>
        /// <param name="hand"></param>
        public void Raise(string hand)
        {
            Console.WriteLine("首领A{0}手举杯",hand);
            //调用举杯事件，传入或者右手作为参数
            if (RaiseEvent != null)
            {
                RaiseEvent(hand);

            }
        }
        /// <summary>
        ///调用摔杯事件
        /// </summary>
        public void Fall()
        {
            Console.WriteLine("首领A摔杯");
            //调用摔杯事件
            if (FallEvent!= null)
            {
                FallEvent();
            }
            Console.ReadKey();
        
        }
              
    }
    public class B
    {
        A a;
        public B(A a)
        {
            this.a = a;
            a.RaiseEvent += new RaiseEventHandler(a_RaiseEvent);//订阅举杯事件
            a.FallEvent += new FallEventHandler(a_FallEvent);//订阅摔杯事件

        }
        /// <summary>
        /// 首领举杯时的动作
        /// </summary>
        /// <param name="hand"></param>
        void a_RaiseEvent(string hand)
        {
            if (hand.Equals("左"))
            {
                Attack();
            }

        }
        /// <summary>
        /// 首领摔杯时的动作
        /// </summary>
        void a_FallEvent()
        {
            Attack();
        }
       /// <summary>
       /// 攻击
       /// </summary>
        public void Attack()
        {
            Console.WriteLine("部下B发起攻击，大喊：张飞来也！");
        }

    }
    public class C
    {
        A a;
        public C(A a)
        {
            this.a = a;
            a.RaiseEvent += new RaiseEventHandler(a_RaiseEvent);
            a.FallEvent += new FallEventHandler(a_FallEvent);
        }
        /// <summary>
        /// A举杯时的动作
        /// </summary>
        /// <param name="hand"></param>
        void a_RaiseEvent(string hand)
        {
            if (hand.Equals ("右"))
            {
                Attack();
            }
        }
        /// <summary>
        /// A摔杯子时的动作
        /// </summary>
        void a_FallEvent()
        {
            Attack();
        }

        public void Attack()
        {
            Console.WriteLine("部下C发起进攻，大喊：关羽在此");
        }

    }

}