委托（匿名函数、Lambda表达式）

using System;

namespace ConsoleApp1
{
    /// <summary>
    /// 委托（匿名函数、Lambda表达式）
    /// </summary>
    class Program
    {

        //定义委托
        internal delegate void TestDelegate(string s);
        static void Main(string[] args)
        {
            Func<string> f1 = () => "Jeff";
            //var result= f1();
           
            //.net2.0时期的匿名函数写法
            Func<string> f2 = delegate () { return "Jeff2"; };
            //var result = f2.Invoke();

            //.net3.0以后的Lambda表达式写法
            //Func<Int32, string> f3 = (Int32 i) => i.ToString();
            Func<Int32, string> f3 = (i) => i.ToString();
            var result = f3(100);

            Func<Int32, string> f4 = delegate (Int32 i) { return i.ToString(); };
            //var result = f4(1000);

            //Console.WriteLine(result);
            //Console.ReadKey();

            //1.实例化委托
            TestDelegate testDelegate1 = new TestDelegate(ConsoleStr);
            testDelegate1("测试委托1");

            //2.匿名委托（.NET2.0 +）
            TestDelegate testDelegate2 = delegate (string s) { Console.WriteLine(s); };
            testDelegate2.Invoke("测试委托2");

            //3.Lambda表达式
            TestDelegate testDelegate3 = (s) => { Console.WriteLine(s); };
            testDelegate3("测试委托3");  
        }

        static void ConsoleStr(string s)
        {
            Console.WriteLine(s);
        }
}
}