异步执行与预期不同

Question

在下面的代码片段中    private async void FinishCommandExecute()    {        Console.WriteLine("FinishCommandExecute_1");        _granularBlobAnalyzer.SaveResult(SampleID, Operator, Comments);        Console.WriteLine("FinishCommandExecute_2");        await Task.Run(() => FlushCommandExecute());        Console.WriteLine("FinishCommandExecute_3");        State = GBAState.IDLE;        Console.WriteLine("FinishCommandExecute_4");    }    private async void FlushCommandExecute()    {        Console.WriteLine("FlushCommandExecute_1");        State = GBAState.FLUSHING;        Console.WriteLine("FlushCommandExecute_2");        await Task.Run(() => _granularBlobAnalyzer.Flush()); // Task to wrap sync method        Console.WriteLine("FlushCommandExecute_3");        State = GBAState.STOPPED;        Console.WriteLine("FlushCommandExecute_4");    }我调用 FinishCommandExecute （它作为命令绑定到一个按钮），我希望完成命令会调用刷新命令并等待它完成，但它不会等待刷新命令内的等待...并且执行继续如果您查看评论，我希望控制台中出现以下内容完成命令执行_1完成命令执行_2FlushCommandExecute_1FlushCommandExecute_2FlushCommandExecute_3FlushCommandExecute_4完成CommandExecute_3完成CommandExecute_4而实际情况是：完成命令执行_1完成命令执行_2FlushCommandExecute_1FlushCommandExecute_2完成CommandExecute_3完成CommandExecute_4FlushCommandExecute_3FlushCommandExecute_4为什么异步方法不等待第二个异步方法中的任务运行

Answer 1

FlushCommandExecute是async void，因此它运行时未观察到，您无法等待\等待它，除非您使用某种同步机制（如AutoResetEvent等）或重构代码来调用async Task并等待它。

private async void FlushCommandExecute() => await FlushCommand();

private async void FinishCommandExecute()

{

    ...

    await FlushCommand();

    ...

}

private async Task FlushCommand()

{

     ...

}