匿名方法，Action,Func以及lambda的区别

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

namespace ConsoleApplication1
{
    public delegate int GetSum(object index);

    class Program
    {
        static void Main(string[] args)
        {
            /*
            Task task = new Task(new Action(Test));
            task.Start();
            Console.Read();
            */

            //最初的正确方法
            //Task<int> task = new Task<int>(n=>Sum((Int32)n), 100);

            //正确的定义方法一
            Task<int> task = new Task<int>(new Func<object,int>(Sum),10);

            //错误的定义方法二
            //Task<int> task1 = new Task<int>(new Func<in object,out int>(Sum), 20);

            //方法三错误
            GetSum getSum = new GetSum(Sum);
            Task<int> task1 = new Task<int>((Func<object, int>)getSum, 20);

            Console.WriteLine("Current Status:"+task.Status);
            task.Start();
            Console.WriteLine("Current Status:" + task.Status);
            Console.WriteLine(task.Result);
            Thread.Sleep(60);
            Console.WriteLine("Current Status:" + task.Status);
            Console.Read();
        }

        private static void Test() {
            Console.WriteLine("Hello,World!");
        }

        //正确的方法一
        private static int Sum(object input)
        {
            int result = 0;
            for (int i = 0; i < (int)input;i++ )
            {
                checked
                {
                    result += i;
                }
                //result=checked(result+i);
            }
            return result;
        }

        //正确的方法二
        private static int SumSecond(int input)
        {
            int result = 0;
            for (int i = 0; i < (int)input; i++)
            {
                checked
                {
                    result += i;
                }
                //result=checked(result+i);
            }
            return result;
        }
    }
}

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

namespace ConsoleApplication1
{
    public delegate int GetSum(object index);

    class Program
    {
        static void Main(string[] args)
        {
            /*
            Task task = new Task(new Action(Test));
            task.Start();
            Console.Read();
            */

            //最初的正确方法
            //Task<int> task = new Task<int>(n=>Sum((Int32)n), 100);    //注意这里的（Int32）强制转换

            //正确的定义方法一
            Task<int> task = new Task<int>(new Func<object,int>(Sum),10);

            //错误的定义方法二
            //Task<int> task1 = new Task<int>(new Func<in object,out int>(Sum), 20);

            //方法三错误
            //GetSum getSum = new GetSum(Sum);
            //Task<int> task1 = new Task<int>((Func<object, int>)getSum, 20);

            //方法四
            Task<int> taskForth = new Task<int>(delegate(object input) { return 100; }, 30);

            Console.WriteLine("Current Status:"+task.Status);
            task.Start();
            Console.WriteLine("Current Status:" + task.Status);
            Console.WriteLine(task.Result);
            Thread.Sleep(60);
            Console.WriteLine("Current Status:" + task.Status);
            taskForth.Start();
            Console.WriteLine(taskForth.Result);
            Console.Read();
        }

        private static void Test() {
            Console.WriteLine("Hello,World!");
        }

        //正确的方法一
        private static int Sum(object input)
        {
            int result = 0;
            for (int i = 0; i < (int)input;i++ )
            {
                checked
                {
                    result += i;
                }
                //result=checked(result+i);
            }
            return result;
        }

        //正确的方法二
        private static int SumSecond(int input)
        {
            int result = 0;
            for (int i = 0; i < (int)input; i++)
            {
                checked
                {
                    result += i;
                }
                //result=checked(result+i);
            }
            return result;
        }
    }
}