c#-异步/等待超出预期顺序

我正试图了解我编写的一个示例的结果。这是：

    class Program
    {
        static async Task Main(string[] args)
        {
            var counter1 = new Counter("counter1",string.Empty);
            var counter2 = new Counter("counter2","         ");
            var counter3 = new Counter("counter3","                     ");            

            await Task.WhenAll(counter1.Count(), counter2.Count(), 
counter3.Count());         
        }
    }

public class Counter
    {
        private string _name;
        private string _prefix;

        public Counter(string name, string prefix)
        {
            _name = name;
            _prefix = prefix;
        }

        public async Task Count()
        {
            for (int i = 0; i <= 10; i++)
            {
                Console.Write($"{_prefix}{_name}: {i}");
                if (i % 2 == 0 && i != 0)
                {
                    Console.WriteLine($" is divisible by 2. Yielding");
                    await Task.Yield();
                }
                else
                {
                    Console.WriteLine();
                }
            }
        }
    }

为何不维持秩序

编辑1：

我已经添加了threadId。似乎线程一直在切换。为什么呢？我的平台是Windows上的.NET核心控制台应用程序

counter1: 0. ThreadId: 1
counter1: 1. ThreadId: 1
counter1: 2. ThreadId: 1 is divisible by 2. Yielding
         counter2: 0. ThreadId: 1
         counter2: 1. ThreadId: 1
         counter2: 2. ThreadId: 1 is divisible by 2. Yielding
                     counter3: 0. ThreadId: 1
                     counter3: 1. ThreadId: 1
                     counter3: 2. ThreadId: 1 is divisible by 2. Yielding
counter1: 3. ThreadId: 3
counter1: 4. ThreadId: 3 is divisible by 2. Yielding
                     counter3: 3. ThreadId: 4
                     counter3: 4. ThreadId: 4 is divisible by 2. Yielding
                     counter3: 5. ThreadId: 4
                     counter3: 6. ThreadId: 4 is divisible by 2. Yielding
counter1: 5. ThreadId: 3
counter1: 6. ThreadId: 3 is divisible by 2. Yielding
                     counter3: 7. ThreadId: 4
                     counter3: 8. ThreadId: 4 is divisible by 2. Yielding
                     counter3: 9. ThreadId: 4
                     counter3: 10. ThreadId: 4 is divisible by 2. Yielding
counter1: 7. ThreadId: 3
counter1: 8. ThreadId: 3 is divisible by 2. Yielding
counter1: 9. ThreadId: 3
counter1: 10. ThreadId: 3 is divisible by 2. Yielding
         counter2: 3. ThreadId: 5
         counter2: 4. ThreadId: 5 is divisible by 2. Yielding
         counter2: 5. ThreadId: 5
         counter2: 6. ThreadId: 5 is divisible by 2. Yielding
         counter2: 7. ThreadId: 5
         counter2: 8. ThreadId: 5 is divisible by 2. Yielding
         counter2: 9. ThreadId: 5
         counter2: 10. ThreadId: 5 is divisible by 2. Yielding

---

您位于控制台应用程序中，因此默认情况下没有同步上下文。在第一个

wait

运行后，它的继续将被安排在另一个线程池线程上。在主线程上，第二个计数器启动，当它再次到达

await

时，它将产生另一个“分支”。这些将并行运行，您将失去预期的顺序

---

如果希望一次只运行一个任务，则需要使用同步上下文或只调度一个线程的任务计划程序。

请将

控制台.WriteLine（System.Threading.thread.CurrentThread.ManagedThreadId.ToString（））

添加到循环中并发布结果。此外，请标记平台/应用程序类型，例如.NET Core vs.Framework和WinForms vs.ASP.NET等，因为它们都略有不同。

可能重复。我希望Task.Whalll为：1。采取其中一种方法并执行它

，它不是这样工作的。当您调用

.Count（）

时，该方法开始执行

Task.WhenAll

只是等待，但我确实在这一行中调用了.Count（）：wait Task.WhenAll（counter1.Count（），counter2.Count（），counter3.Count（））；然后呢？这严格等同于

var task1=counter1.Count（）；var task2=counter2.Count（）；var task3=counter3.Count（）；等待任务。WhenAll（任务1、任务2、任务3）也许这样更容易理解
counter1: 0. ThreadId: 1
counter1: 1. ThreadId: 1
counter1: 2. ThreadId: 1 is divisible by 2. Yielding
         counter2: 0. ThreadId: 1
         counter2: 1. ThreadId: 1
         counter2: 2. ThreadId: 1 is divisible by 2. Yielding
                     counter3: 0. ThreadId: 1
                     counter3: 1. ThreadId: 1
                     counter3: 2. ThreadId: 1 is divisible by 2. Yielding
counter1: 3. ThreadId: 3
counter1: 4. ThreadId: 3 is divisible by 2. Yielding
                     counter3: 3. ThreadId: 4
                     counter3: 4. ThreadId: 4 is divisible by 2. Yielding
                     counter3: 5. ThreadId: 4
                     counter3: 6. ThreadId: 4 is divisible by 2. Yielding
counter1: 5. ThreadId: 3
counter1: 6. ThreadId: 3 is divisible by 2. Yielding
                     counter3: 7. ThreadId: 4
                     counter3: 8. ThreadId: 4 is divisible by 2. Yielding
                     counter3: 9. ThreadId: 4
                     counter3: 10. ThreadId: 4 is divisible by 2. Yielding
counter1: 7. ThreadId: 3
counter1: 8. ThreadId: 3 is divisible by 2. Yielding
counter1: 9. ThreadId: 3
counter1: 10. ThreadId: 3 is divisible by 2. Yielding
         counter2: 3. ThreadId: 5
         counter2: 4. ThreadId: 5 is divisible by 2. Yielding
         counter2: 5. ThreadId: 5
         counter2: 6. ThreadId: 5 is divisible by 2. Yielding
         counter2: 7. ThreadId: 5
         counter2: 8. ThreadId: 5 is divisible by 2. Yielding
         counter2: 9. ThreadId: 5
         counter2: 10. ThreadId: 5 is divisible by 2. Yielding