.NET Web服务和放大器; BackgroundWorker的线程 [英] .NET Web Service & BackgroundWorker threads

问题描述

我试图做一些异步的东西，在一个Web服务方法。让说我有以下API调用： http://www.mysite.com/api.asmx

I'm trying to do some async stuff in a webservice method. Let say i have the following API call: http://www.mysite.com/api.asmx

和该方法被调用的的GetProducts（）的

我这样的GetProducts方法，我做一些东西（如从数据库中获得的数据），那么就在我返回的结果，我想要做一些异步的东西（如：给我发送电子邮件）。

I this GetProducts methods, i do some stuff (eg. get data from database) then just before i return the result, i want to do some async stuff (eg. send me an email).

所以这就是我所做的。

[WebMethod(Description = "Bal blah blah.")]
public IList<Product> GetProducts()
{
    // Blah blah blah ..
    // Get data from DB .. hi DB!
    // var myData = .......
    // Moar clbuttic blahs :)  (yes, google for clbuttic if u don't know what that is)

    // Ok .. now send me an email for no particular reason, but to prove that async stuff works.
    var myObject = new MyObject();
    myObject.SendDataAsync();

    // Ok, now return the result.
    return myData;
    }
}

public class TrackingCode
{
    public void SendDataAsync()
    {
        var backgroundWorker = new BackgroundWorker();
        backgroundWorker.DoWork += BackgroundWorker_DoWork;
        backgroundWorker.RunWorkerAsync();
        //System.Threading.Thread.Sleep(1000 * 20);
    }

    private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        SendEmail();
    }
}

现在，当我运行该code中的邮件永远不会发送。如果我取消了Thread.sleep代码..然后发送电子邮件。

Now, when i run this code the email is never sent. If i uncomment out the Thread.Sleep .. then the email is sent.

所以......那为什么后台工作线程被拆除？它是依赖于父线程呢？这是错误的方式，我应该做的背景或分叉线程，在asp.net web应用程序？

So ... why is it that the background worker thread is torn down? is it dependant on the parent thread? Is this the wrong way i should be doing background or forked threading, in asp.net web apps?

欢呼;）

推荐答案

的BackgroundWorker 当你需要同步回（例如）UI *线程，例如，是非常有用的亲和的原因。在这种情况下，它似乎只是使用线程池将绰绰有余（和简单得多）。如果你有大容量，那么生产者/消费者队列可能能够更好地节流（这样你就不会在线程淹没） - 但我怀疑线程池将被罚款这里..

BackgroundWorker is useful when you need to synchronize back to (for example) a UI* thread, eg for affinity reasons. In this case, it would seem that simply using ThreadPool would be more than adequate (and much simpler). If you have high volumes, then a producer/consumer queue may allow better throttling (so you don't drown in threads) - but I suspect ThreadPool will be fine here...

public void SendDataAsync()
{
    ThreadPool.QueueUserWorkItem(delegate
    {
        SendEmail();
    });
}

此外 - 我不太清楚你想睡觉达到什么样的？这只会占用一个线程（不使用CPU，但无论哪种做得没有好）。详细地谈一谈？它的看起来的就像你暂停您的实际网页（即睡眠发生在Web页主题，而不是邮件线程）。什么是你想在这里做什么？

Also - I'm not quite sure what you want to achieve by sleeping? This will just tie up a thread (not using CPU, but doing no good either). Care to elaborate? It looks like you are pausing your actual web page (i.e. the Sleep happens on the web-page thread, not the e-mail thread). What are you trying to do here?

* =实际上，它会使用任何同步上下文是代替

*=actually, it will use whatever sync-context is in place

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