委托例子

//委托例子
/*委托是一个类，它定义了方法的类型，使得可以将方法当作另一个方法的参数来进行传递，
这种将方法动态地赋给参数的做法，可以避免在程序中大量使用If-Else(Switch)语句，
同时使得程序具有更好的可扩展性。
*/
//之一
using System;
// Declare delegate -- defines required signature:
delegate void SampleDelegate(string message);

class MainClass
{
    // Regular method that matches signature:
    static void SampleDelegateMethod(string message)
    {
        Console.WriteLine(message);
    }

    static void Main()
    {
        // Instantiate delegate with named method:
        SampleDelegate d1 = SampleDelegateMethod;
        // Instantiate delegate with anonymous method:
        SampleDelegate d2 = delegate(string message)
        {
            Console.WriteLine(message);
        };

        // Invoke delegate d1:
        d1("Hello");
        // Invoke delegate d2:
        d2(" World");
    }
}


//之二
using System;
using System.Collections.Generic;
using System.Text;
namespace Delegate
{
    //定义委托，它定义了可以代表的方法的类型
    public delegate void GreetingDelegate(string name);
    class Program
    {
        private static void EnglishGreeting(string name)
        {
            Console.WriteLine("Morning, " + name);
        }
        private static void ChineseGreeting(string name)
        {
            Console.WriteLine("早上好, " + name);
        }
        //注意此方法，它接受一个GreetingDelegate类型的方法作为参数
        private static void GreetPeople(string name, GreetingDelegate MakeGreeting)
        {
            MakeGreeting(name);
        }
        static void Main(string[] args)
        {
            GreetPeople("Jimmy Zhang", EnglishGreeting);
            GreetPeople("张子阳", ChineseGreeting);
            Console.ReadKey();
        }
    }
}



//委托写在两个类
//1
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Delegate
{
    class GreetingManager
    {
        public event GreetingDelegate delegate1;
        public void GreetPeople(string name, GreetingDelegate MakeGreeting)
        {
            MakeGreeting(name);
        }
    }
}

//2
using System;
using System.Collections.Generic;
using System.Text;
namespace Delegate
{
    //定义委托，它定义了可以代表的方法的类型
    public delegate void GreetingDelegate(string name);
    class Program
    {
        private static void EnglishGreeting(string name)
        {
            Console.WriteLine("Morning, " + name);
        }
        private static void ChineseGreeting(string name)
        {
            Console.WriteLine("早上好, " + name);
        }

        static void Main(string[] args)
        {
            GreetingManager gm = new GreetingManager();
            GreetingDelegate delegate1;
            delegate1 = EnglishGreeting;
            delegate1 += ChineseGreeting;
            gm.GreetPeople("Jimmy Zhang", delegate1);
            Console.ReadKey();
        }
    }
}
//结束