带有异步 lambda 和 Task.WaitAll 的 Task.Factory.StartNew [英] Task.Factory.StartNew with async lambda and Task.WaitAll

问题描述

我正在尝试对任务列表使用 Task.WaitAll.问题是任务是一个异步 lambda，它打破了 Tasks.WaitAll 因为它从不等待.

I'm trying to use Task.WaitAll on a list of tasks. The thing is the tasks are an async lambda which breaks Tasks.WaitAll as it never waits.

这是一个示例代码块:

List<Task> tasks = new List<Task>();
tasks.Add(Task.Factory.StartNew(async () =>
{
    using (dbContext = new DatabaseContext())
    {
        var records = await dbContext.Where(r => r.Id = 100).ToListAsync();
        //do long cpu process here...
    }
}
Task.WaitAll(tasks);
//do more stuff here  

由于异步 lambda，这不会等待.那么我应该如何在我的 lambda 中等待 I/O 操作?

This doesn't wait because of the async lambda. So how am I supposed to await I/O operations in my lambda?

推荐答案

Task.Factory.StartNew 无法识别 async 委托，因为没有重载接受函数返回一个 Task.

Task.Factory.StartNew doesn't recognise async delegates as there is no overload that accepts a function returning a Task.

这加上其他原因(请参阅StartNew 很危险)是您应该在此处使用 Task.Run:

This plus other reasons (see StartNew is dangerous) is why you should be using Task.Run here:

tasks.Add(Task.Run(async () => ...

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