c#委托

示例1:

 

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

namespace ConsoleApplication1
{
    delegate void EatDelegate(String food);

    class Program
    {
        private static void zsEat(String food)
        {
            Console.WriteLine("张三吃"+food);
        }

        private static void lsEat(String food)
        {
            Console.WriteLine("李四吃"+food);
        }

        private static void wwEat(String food)
        {
            Console.WriteLine("王五吃"+food);
        }

        static void Main(string[] args)
        {
            /*定义张三,李四,王五吃food的委托,
             * 并为他们的委托代理他们吃food的方法.*/
            EatDelegate zs = new EatDelegate(zsEat);

            EatDelegate ls = new EatDelegate(lsEat);

            EatDelegate ww = new EatDelegate(wwEat);

            //委托链
            EatDelegate eatChain = zs + ls + ww;

            Console.WriteLine("张三,李四,王五开座谈会.");

            //调用委托链
            eatChain("吃西瓜");

            Console.WriteLine("李四出去接电话.");

            /*C#在委托中重载了+=和-=操作符,
             * 使它们能够对委托链进行+,-操作*/
            eatChain -= ls;

            eatChain("吃香蕉");

            Console.WriteLine("李四回来了.");

            eatChain += ls;

            eatChain("吃桔子.");

        }
    }
}

 

 委托的匿名方法:

 

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

namespace ConsoleApplication1
{
    delegate void EatDelegate(String food);

    class Program
    {
        static void Main(string[] args)
        {
         
            //委托链
            EatDelegate eatChain=null;

            //C#2.0增加的委托的匿名方法
            eatChain += delegate(String food) { Console.WriteLine("张三吃"+food); };

            eatChain += delegate(String food) { Console.WriteLine("李四吃"+food); };

            eatChain += delegate(String food) { Console.WriteLine("王五吃" + food); };

            eatChain("西瓜");

        }
    }
}

 

 委托代理实例方法

 

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

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(name+"吃"+food);
        }
    }


    /*委托代理实例方法*/
    class Party
    {
        [STAThread]
        static void Main(string[] args)
        {

            Man zsObj = new Man("张三");

            Man lsObj = new Man("李四");

            Man wwObj = new Man("王五");

            EatDelegate zs = new EatDelegate(zsObj.Eat);

            EatDelegate ls = new EatDelegate(lsObj.Eat);

            EatDelegate ww = new EatDelegate(wwObj.Eat);
         
            //委托链
            EatDelegate eatChain=zs+ls+ww;

            Console.WriteLine("张三,李四,王五开座谈会.");

            eatChain("吃西瓜");

            Console.WriteLine("李四出去接电话.");

            eatChain -= ls;

            eatChain("吃香蕉");

            Console.WriteLine("李四回来了.");

            eatChain("吃桔子");
        }
    }
}

 

 委托当作方法参数进行调用：

 

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

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(name+"吃"+food);
        }
    }


    /*委托作为方法的参数进行传递*/
    class Party
    {
        /// <summary>
        /// 委托作为参数进行传递
        /// </summary>
        /// <param name="food">吃的东西</param>
        /// <param name="values">可变的委托参数</param>
        static void EatToghter(String food, params EatDelegate[] values)
        {
            if (values==null)
            {
                Console.WriteLine("座谈会结束");
            }
            else
            {
                EatDelegate eatChain = null;

                foreach (EatDelegate eat in values)
                    eatChain += eat;

                eatChain(food);

                Console.WriteLine();
            }
        }

        [STAThread]
        static void Main(string[] args)
        {

            Man zsObj = new Man("张三");

            Man lsObj = new Man("李四");

            Man wwObj = new Man("王五");

            EatDelegate zs = new EatDelegate(zsObj.Eat);

            EatDelegate ls = new EatDelegate(lsObj.Eat);

            EatDelegate ww = new EatDelegate(wwObj.Eat);
         
            //委托链
            EatDelegate eatChain=zs+ls+ww;

            Console.WriteLine("张三,李四,王五开座谈会.");
            
            //调用委托作为参数的方法
            EatToghter("西瓜",zs,ls,ww);

            Console.WriteLine("李四出去接电话.");
            
            //没有传递李四的委托
            EatToghter("香蕉", zs, ww);

            Console.WriteLine("李四回来了.");
            
            //三个人继续吃香蕉
            EatToghter("香蕉", zs, ls, ww);

            EatToghter(null,null);
        }
    }
}