此异步方法缺少“等待"运算符，将同步运行 [英] This async method lacks 'await' operators and will run synchronously

问题描述

我的程序对以下语句有3条警告:

my program has 3 warnings of the following statement:

此异步方法缺少等待"运算符，将同步运行. 考虑使用"await"运算符来等待非阻塞API调用， 或"await Task.Run(...)"在后台线程上执行CPU绑定的工作.

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

尝试告诉我什么警告?我该怎么办?

What is the warning try to tell me? What should I do?

这是我的代码:它是否在使用多线程运行?

This is my code: Is it running using multi-threading?

static void Main(string[] args)
{
    Task task1 = new Task(Work1);
    Task task2 = new Task(Work2);
    Task task3 = new Task(Work3);

    task1.Start();
    task2.Start();
    task3.Start();

    Console.ReadKey();
}

static async void Work1()
{
    Console.WriteLine("10 started");
    Thread.Sleep(10000);
    Console.WriteLine("10 completed");
}

static async void Work2()
{
    Console.WriteLine("3 started");
    Thread.Sleep(3000);
    Console.WriteLine("3 completed");
}

static async void Work3()
{
    Console.WriteLine("5 started");
    Thread.Sleep(5000);
    Console.WriteLine("5 completed");
}

推荐答案

async关键字本身并不能真正起到很大作用.从您的代码中删除它，您的代码将完全相同.

The async keyword, by itself, doesn't really do much. Remove it from your code and your code will act exactly the same.

async的作用是什么?

• 它更改了方法内部的有效内容，特别是它允许您使用await关键字
• 反过来，这意味着将根据方法主体中存在的await来转换方法主体.
• 如果该方法返回值，则该方法也将转换为将返回值包装在Task中.

• It changes what's valid inside of the method, specifically it allows you to use the await keyword
• In turn, it means that the body of the method will be transformed, based on the awaits that are present in the body of the method.
• And if the method returns a value, the method is also transformed to wrap the return value in a Task.

但是，如果您a)方法主体中没有任何await，并且b)返回了void，那么将不会实现任何特殊操作.编译器警告确实尝试澄清这一点-没有任何await的async方法没有任何意义. await s是此功能的更重要部分.

However, if you a) Don't have any awaits in your method body and b) are void returning, then nothing special will be achieved. The compiler warning does try to be clear about this - an async method without any awaits just plain doesn't make sense. awaits are the more important part of this feature.

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