C#

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

namespace 委托_泛型
{
    class Program
    {
        // 声明委托(无参,无返回值)
        delegate void DG();

        static void Main(string[] args)
        {
            // 1.委托调用:SayHelloInChinese()
            DG dg = SayHelloInChinese;
            dg();
         
            // 2.委托调用:SayHelloInEnglish()
            dg = SayHelloInEnglish;
            dg();

            Console.WriteLine("
===================
");

            // 3. Action泛型委托: 无参, 无返回值  
            Action dg1 = SayHelloInChinese;
            dg1();

            // 4. Action泛型委托: 带参, 无返回值
            Action<string>dg2 = SayHelloInEnglish;
            dg2("张三");

            Console.WriteLine("
===================
");

            // 5. Func泛型委托 : 有参  有返回值   
            Func<double, double, double> add = Add;
            double result = add(3.0, 4.0);
            Console.WriteLine("result = {0}", result);



            Console.ReadLine();
        }


        static void SayHelloInChinese()
        {
            Console.WriteLine("你好! ");
        }

        static void SayHelloInChinese(string name)
        {
            Console.WriteLine("你好! {0}", name);
        }

        static void SayHelloInEnglish()
        {
            Console.WriteLine("Hello! ");
        }

        static void SayHelloInEnglish(string name)
        {
            Console.WriteLine("Hello! {0}", name);
        }

        static double Add(double a, double b)
        {
            return a + b;
        }

    }
}