委托

1

    class Program
    {
        private delegate string GetAStr();

        static void Main(string[] args)
        {
            //int x = 40;
            //string s = x.ToString();

            //Console.WriteLine(s);

            //GetAStr getAStr = new GetAStr(x.ToString);

            //Console.WriteLine(getAStr.Invoke());

            PrintStr method = Method1;
            Printf(method);
            method = Method2;
            Printf(method);
            Console.ReadKey();


        }

        private delegate void PrintStr();
        static void Printf(PrintStr print)
        {
            print();
        }

        static void Method1()
        {
            Console.WriteLine("method1");
        }
        static void Method2()
        {
            Console.WriteLine("method2");
        }
    }

2 action

    class Program
    {
        static void PrintStr(int i)
        {
            Console.WriteLine(i);
        }

        static void PrintStr(string s)
        {
            Console.WriteLine(s);
        }
        static void PrintStr(string s, int i)
        {
            Console.WriteLine(s);
        }


        static void Main(string[] args)
        {
            //int x = 100;
            //Action a = PrintStr;
            //Action<int> a = PrintStr;
            Action<string, int> a = PrintStr;
 
        }
    }

3 func

    class Program
    {
        static int Test1()
        {
            return 1;
        }
        static int Test2(string s)
        {
            //Console.WriteLine(s);
            return 100;
        }

        static void Main(string[] args)
        {
            Func<string,int> a = Test2;
            Console.WriteLine(a("sad"));
            Console.ReadKey();
        }
    }