C#视频

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

namespace ConsoleApplication1
{

    delegate void EatDelegate(string food);

    class Program
    {
        static void JimEat(string food)
        {
            Console.WriteLine("Jim eats " + food);
        }
        static void DavidEat(string food)
        {
            Console.WriteLine("David eats " + food);
        }
        static void TimEat(string food)
        {
            Console.WriteLine("Tim eats " + food);
        }

        static void Main(string[] args)
        {
            EatDelegate jim = new EatDelegate(JimEat);
            EatDelegate david = new EatDelegate(DavidEat);
            EatDelegate tim = new EatDelegate(TimEat);
            jim("Apple");
            david("Apple");
            tim("Apple");

            // 委托链
            EatDelegate ed;
            ed = jim + tim + david;


            foreach(EatDelegate e in ed.GetInvocationList())
            {
                Console.WriteLine(e.Method.Name);
            }

            ed("apple");

            ed -= tim;

            ed("orange");

            // 匿名方法
            EatDelegate ed1 = null;
            ed1 += delegate (string food){ Console.WriteLine("A eats " + food);};
            ed1 += delegate(string food) { Console.WriteLine("B eats " + food); };
            ed1.Invoke("pineapple");

            Console.ReadLine();
        }
    }
}

委托的本职就是一个Class，任何可以声明Class的地方都可以声明委托。

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

namespace ConsoleApplication1
{

    delegate void EatDelegate(string food);

    class Program
    {
        static void JimEat(string food)
        {
            Console.WriteLine("Jim eats " + food);
        }
        static void DavidEat(string food)
        {
            Console.WriteLine("David eats " + food);
        }
        static void TimEat(string food)
        {
            Console.WriteLine("Tim eats " + food);
        }

        static void Main(string[] args)
        {
            EatDelegate jim = new EatDelegate(JimEat);
            EatDelegate david = new EatDelegate(DavidEat);
            EatDelegate tim = new EatDelegate(TimEat);
            jim("Apple");
            david("Apple");
            tim("Apple");

            // 委托链
            EatDelegate ed;
            ed = jim + tim + david;


            foreach(EatDelegate e in ed.GetInvocationList())
            {
                Console.WriteLine(e.Method.Name);
            }

            ed("apple");

            ed -= tim;

            ed("orange");

            // 匿名方法
            EatDelegate ed1 = null;
            ed1 += delegate (string food){ Console.WriteLine("A eats " + food);};
            ed1 += delegate(string food) { Console.WriteLine("B eats " + food); };
            ed1.Invoke("pineapple");

            Console.ReadLine();
        }
    }
}

委托链，可以通过GetInvocationList（）获取委托链中的每个委托元素，进而获取每个元素的方法名称，返回值类型等。

还可以通过delegate声明匿名函数。

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

namespace ConsoleApplication1
{

    delegate void EatDelegate(string food);

    class Man
    {
        private string name;

        public Man(string name)
        {
            this.name = name;
        }

        public void eat(string food)
        {
            Console.WriteLine("{0} eats {1}", name, food);
        }
    }

    class Program
    {

        static void eatTogether(string food, params EatDelegate[] values)
        {
            if (values == null)
            {
                Console.WriteLine("Party is over.");
            }
            else
            {
                EatDelegate ed = null;
                foreach(EatDelegate e in values)
                {
                    ed += e;
                }

                ed(food);
                Console.WriteLine();
            }
        }

        static void Main(string[] args)
        {
            Man jim = new Man("Jim");
            Man david = new Man("David");
            Man tim = new Man("Tim");
            Man jun = new Man("Jun");

            // 动态方法
            EatDelegate jimED = new EatDelegate(jim.eat);
            EatDelegate davidED = new EatDelegate(david.eat);
            EatDelegate timED = new EatDelegate(tim.eat);
            EatDelegate junED = new EatDelegate(jun.eat);

            EatDelegate ed = null;
            ed = jimED + davidED + timED + junED;
            ed("orange");

            eatTogether("pig", davidED, jimED, junED);

            eatTogether("egg", timED, davidED);

            eatTogether(null, null);

            Console.ReadLine();
        }
    }
}

Note： 动态方法。