AsTask不存在实行取消超时异步读 [英] AsTask doesn't exist to implement a cancellation timeout for Async Read

问题描述

我渴望加入超时功能，以我的 stream.ReadAsync（）并阅读微软在这篇文章中帮助的异步取消：.NET Framework和Windows运行时（C＃和Visual Basic）之间的桥接。本文建议使用 AsTask（）来实现这一目标。但是我的C＃似乎并没有认识到 AsTask（）的。

I am eager to add a time-out feature to my stream.ReadAsync() and read Microsoft help in this article Async Cancellation: Bridging between the .NET Framework and the Windows Runtime (C# and Visual Basic). This article suggests to use AsTask() to make this happen. However my C# doesn't seem to recognize AsTask() at all.

我使用的的Visual Studio 2013 是 Windows 7中与使用的System.Threading; ，这是一张code，我有：

I am using Visual Studio 2013 with Windows 7 along with using System.Threading; and this is the piece of code I have:

private async Task<int> ReadAsync(BluetoothClient Client)
{
    const int timeoutMs = 10000;
    var cancelationToken = new CancellationTokenSource(timeoutMs);


    var stream = Client.GetStream();
    byte[] buffer = { 0 };
    int offset = 0;
    int count = 1;
    StatusManager("~Async Read Started...");

    //This line works perfectly fine.
    var rx = await stream.ReadAsync(buffer, offset, count);
    //This line gets underlined with error for AsTask()
    var rx = await stream.ReadAsync(buffer, offset, count).AsTask(cancelationToken);
    //rx.AsTask().Start();
    StatusManager("Recieved byte " + rx.ToString());
    StatusManager("~Async Read Finished.");
}

我是什么在这里缺少人。我百思不得其解：）

What am I missing here folks. I am puzzled :)

更新：这是安装.NET软件包列表，我想说的Visual Studio 2013采用4.5

UPDATE: These are the list of .NET packages installed and I would say Visual Studio 2013 uses 4.5

推荐答案

由于@Noseratio评论说，在 AsTask 中的链接文章是WinRT的异步操作，没有首创置业类型

As @Noseratio commented, the AsTask in the linked article is for WinRT asynchronous operations, not BCL types.

在你的情况，你可以直接通过取消标记的方法：

In your case, you can just pass the cancellation token directly to the method:

var cancelationToken = new CancellationTokenSource(timeoutMs).Token;
...
var rx = await stream.ReadAsync(buffer, offset, count, cancellationToken);

这篇关于AsTask不存在实行取消超时异步读的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！