問題描述

我發(fā)現(xiàn)自己想要實(shí)現(xiàn)一個 IAwaitable 類(實(shí)現(xiàn)異步調(diào)用而不阻塞線程的東西).

I found myself wanting to implement an IAwaitable class (something that implements asynchronous calls without blocking threads).

我安裝了最新版本的 AsyncCTP，編譯器說我需要一個 IsCompleted() 成員.好的，所以 CTP 預(yù)覽已經(jīng)移動了一點(diǎn)(我明白了，就像預(yù)覽一樣)

I've got the most recent version of AsyncCTP installed, and the compiler is saying that I need an IsCompleted() member. Okay, so the CTP preview has moved on a little bit (I get that, like it's a preview)

問題:現(xiàn)在AsyncCTP 語言擴(kuò)展期望什么接口?

Question: What interface are the AsyncCTP language extensions expecting now?

問題: 在所有這些中，我假設(shè)我可以通過 lamda/delegate 向IAwaitable"發(fā)出信號?這可能嗎?我們叫 EndAwait 嗎?智能感知建議您調(diào)用 EndAwait 來檢索結(jié)果......所以這聽起來不對.有什么想法嗎?

Question: In all this I'm assuming that I can signal to the "IAwaitable" via a lamda/delegate? Is this possible? Do we call EndAwait? The intellisense suggests that you call EndAwait to retrieve the result... so that doesn't sound right. Any ideas?

到目前為止，我發(fā)現(xiàn)的所有示例都針對 AsyncCTP 庫已經(jīng)實(shí)現(xiàn)的功能，例如:

All of the examples I've found so far are for features that the AsyncCTP library has already implemented such as:

  await new WebClient().DownloadStringTaskAsync(uri).ConfigureAwait(false);

來自 101 AsyncSamplesCS

背景:

我發(fā)現(xiàn)自己在 Jon Skeets 頁面上(再次)查看 這個例子

I find myself on Jon Skeets page (again) looking at this example

using System;

class Test
{
    static async void Main()
    {
        await new Awaitable();
    }
}

class Awaitable
{
    public Awaiter GetAwaiter()
    {
        return new Awaiter();
    }
}

class Awaiter
{
    public bool BeginAwait(Action continuation)
    {
        return false;
    }

    public int EndAwait()
    {
        return 1;
    }
}

推薦答案

隨著 SP1 的更新，您需要:

With the SP1 refresh, you need:

• 某些 GetAwaiter() 方法(可能但不一定是擴(kuò)展方法)返回某些內(nèi)容(在您的示例中為 Awaiter)，其中包含以下所有內(nèi)容:
  • 一個 bool IsCompleted 屬性 (get)
  • A void OnCompleted(Action callback)
  • 一個 GetResult() 方法，它返回 void，或等待操作的期望結(jié)果
  • Some GetAwaiter() method (possibly but not necessarily an extension method) that returns something (Awaiter in your example) with all of:
    • A bool IsCompleted property (get)
    • A void OnCompleted(Action callback)
    • A GetResult() method which returns void, or the desired outcome of the awaited operation

    但是，我建議您查看TaskCompletionSource - 我看了這個，結(jié)果出來了- 執(zhí)行我的幼稚實(shí)現(xiàn)(此處；已過時).你也可以將它用于 void 任務(wù)，通過使用類似 TaskCompletionSource 的東西(并利用 Task也是一個無類型的Task).

    However, I suggest you look at TaskCompletionSource<T> - I looked at this, and it out-performed my naive implementation (here; obsolete). You can also use it for void tasks, by using something like a TaskCompletionSource<bool> (and exploit the fact that the Task<bool> is also an untyped Task).

    這篇關(guān)于AsyncCTP:創(chuàng)建一個 IAwaitable 的類的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！

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