1         static void Main(string[] args)
 2         {
 3             callMethod();//方法中 Method1()是在异步中执行，与Method2()之间不相互依赖，Method3()依赖于Method1()
 4             Console.WriteLine("MainEnd");
 5             Console.ReadKey();
 6         }
 7 
 8         public static async void callMethod()
 9         {
10             Task<int> task = Method1();//函数中的sleep模拟异步函数中耗时操作
11             Method2();
12             Console.WriteLine("M2End");
13             Method2_1();//函数中的sleep模拟main函数中的耗时操作
14             Console.WriteLine("M2_1End");
15             int count = await task;
16             Method3(count);
17         }
18 
19         public static async Task<int> Method1()
20         {
21             int count = 0;
22             await Task.Run(() =>
23             {
24                 for (int i = 0; i < 20; i++)
25                 {
26                     Console.WriteLine($" Method 1-{i}");
27                     Thread.Sleep(100);
28                     count += 1;
29                 }
30             });
31             return count;
32         }
33 
34         public static void Method2()
35         {
36             Console.WriteLine($" Method 2");
37         }
38 
39         public static void Method2_1()
40         {
41             for (int i = 0; i < 25; i++)
42             {
43                 Console.WriteLine($" Method 2-{i}");
44                 Thread.Sleep(60);
45             }
46         }
47 
48         public static void Method3(int count)
49         {
50             Console.WriteLine("Total count is " + count);
51         }