异步一次性创建 [英] Async Disposable.Create

问题描述

Disposable.Create 需要Action作为参数. Action在处理Rx订阅时运行.

Disposable.Create require an Action as parameter. The Action is run when the Rx subscription is being disposed.

在处置Rx订阅时，我想运行一些异步清理代码，但是将async () =>与Action结合使用与async void相同，我想避免这种情况.有关为什么要避免这种情况的更多详细信息，请参见此处.

When disposing a Rx subscription I’d like to run some asynchronous clean up code, however using async () => with Action is identical to async void, which I’d like to avoid. For more details on why I want to avoid this, see here.

是否可以创建类似Disposable.AsyncCreate的内容，该内容接受Func<Task>而不是Action.如果是这样，我应该如何将其用作CompositeDisposable的一部分?

Is it possible to create something like a Disposable.AsyncCreate, which accepts Func<Task> rather than Action. If so how should I use it as part of a CompositeDisposable?

或者还有其他处理异步处理的模式吗?

Or are there other patterns for dealing with asynchronous Disposal?

推荐答案

您可以执行以下操作.我仍然不确定这是一个好主意:

You could do something like this. I'm still not sure how good an idea it is:

public class DisposableAsync
{
    private readonly IDisposable _disposable; 
    private readonly Func<Task> _asyncDisposalAction;
    public DisposableAsync(IDisposable disposable, Func<Task> asyncDisposalAction)
    {
        _disposable = disposable;
        _asyncDisposalAction = asyncDisposalAction;
    }

    public Task DisposeAsync()
    {
        _disposable.Dispose();
        return _asyncDisposalAction();
    }
}

public static class DisposableAsyncExtensions
{
    public static DisposableAsync ToAsync(this IDisposable disposable, Func<Task> asyncDisposalAction)
    {
        return new DisposableAsync(disposable, asyncDisposalAction);
    }
}

然后您可以像这样使用它:

You could then use it like this:

async Task Go()
{

    var o = Observable.Interval(TimeSpan.FromMilliseconds(100));
    var d = o
        .Subscribe(i => Console.WriteLine($"{DateTime.Now.ToLongTimeString()}: {i}"))
        .ToAsync(async () =>
        {
            Console.WriteLine($"{DateTime.Now.ToLongTimeString()}: Dispose Beginning");
            await Task.Delay(1000);
            Console.WriteLine($"{DateTime.Now.ToLongTimeString()}: Dispose Complete");
        });
    Console.Read();
    var t = d.DisposeAsync();
    Console.WriteLine($"{DateTime.Now.ToLongTimeString()}: Outside task, waiting for dispose to complete");
    await t;
    Console.WriteLine($"{DateTime.Now.ToLongTimeString()}: Task Complete");

}

此解决方案不适用于using()语句，并且应该增强类DisposableAsync.除此之外，我想不出什么错，但是我对此很反对.只是有点.

This solution wouldn't work with using() statements, and the class DisposableAsync should be robustified. Outside of that, I can't think of anything wrong with it, but I'm predisposed (ahem) against it though. Just feels kind of hacky.

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