C#异步编程

 1 static void Main(string[] args)
 2         {
 3  Console.WriteLine("方法开始："+DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
 4             var strRes = Task.Run(() => {return ReturnStr(); });
 5             Console.WriteLine("方法结束："+DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
 6             for (int i = 0; i < 5; i++)
 7             {
 8                 Console.WriteLine(i);
 9             }
10             Console.WriteLine("得到结果后："+DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
11             Console.WriteLine(strRes.Result);
12             Console.ReadKey();
13         }
14 public static  string  ReturnStr()
15         {
16             Thread.Sleep(2000);
17             return "方法执行后："+ DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss");
18         }

 1 static void Main(string[] args)
 2         {
 3 Console.WriteLine("方法开始：" + DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
 4  ReturnStr();
 5             for (int i = 0; i < 5; i++)
 6             {
 7                 Console.WriteLine(i);
 8             }
 9             Console.WriteLine("方法结束："+DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
10             Console.ReadKey();
11         }
12 
13         public static async  Task ReturnStr()
14         {
15             Console.WriteLine("方法执行开始：" + DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
16             Thread.Sleep(2000);
17             var result=await Task.Run(()=>"方法执行后："+ DateTime.Now.ToString("yyyy-MM-dd hh:MM:ss"));
18             Console.WriteLine(result);
19         }