暇之余，究多Task、async、await。

using System;using System.Collections.Generic;using System.Linq;using System.Linq.Expressions;using System.Text;using System.Threading;using System.Threading.Tasks;namespace ConsoleApp2{    class Program    {        static void Main(string[] args)        {            for (int i = 0; i < 5; i++)            {                Task.Run(() => Run2()); //类似于线程池，开启线程小于5            }            for (int i = 0; i < 5; i++)            {                new Thread(Run1).Start();//开启5个线程            }            Task
     
       task = Task.Run(                () => Thread.CurrentThread.ManagedThreadId + ""            );            Console.WriteLine(task.Result);//task.Result 会等到task执行完毕执行            Console.WriteLine("-------主线程启动-------");            Task
      
        task2 = GetStrLengthAsync();            Console.WriteLine("主线程继续执行");            Console.WriteLine("Task返回的值" + task2.Result);            Console.WriteLine("-------主线程结束-------");        }        static void Run1()        {            Console.WriteLine("Thread Id =" + Thread.CurrentThread.ManagedThreadId);        }        static void Run2()        {            Console.WriteLine("Task调用的Thread Id =" + Thread.CurrentThread.ManagedThreadId);        }        //async必须返回void Task Task
       
                static async Task
        
          GetStrLengthAsync()         {            Console.WriteLine("GetStrLengthAsync方法开始执行");            //await 必须用来修饰Task Task
         
          ,而且只能出现在async修饰的异步方法中。            //遇到await并未开启新线程，而是遇到GetString方法中的Task.Run()时才开启了新线程            string str = await GetString();             Console.WriteLine("GetStrLengthAsync方法结束执行");            return str.Length;        }        static Task
          
            GetString() { Console.WriteLine("GetString方法开始执行"); return Task.Run(() => { Thread.Sleep(2000); return "GetString返回值"; }); } }}