HttpWebRequest.BeginGetResponse [英] HttpWebRequest.BeginGetResponse

问题描述

我需要向Web资源发出异步请求，并使用此页面中的示例(链接到完整示例):

I need to make async request to web resource and use example from this page (link to full example):

HttpWebRequest myHttpWebRequest= (HttpWebRequest)WebRequest.Create("http://www.contoso.com");
RequestState myRequestState = new RequestState();  
myRequestState.request = myHttpWebRequest;
// Start the asynchronous request.
IAsyncResult result=
        (IAsyncResult) myHttpWebRequest.BeginGetResponse(new AsyncCallback(RespCallback),myRequestState);

但是，当我测试应用程序时，此代码最后一行的执行冻结(2-3秒)(我可以使用调试器观看它).

But when I am testing the application the execution freeze(on 2-3 sec) on the last line of this code (i can watch it using debugger).

为什么?是我的错误还是该函数的标准行为?

Why? Is it my mistake or it is a standard behaviour of the function?

推荐答案

您可以尝试一下，我敢肯定那是更好的

You can try, I m sure thats better

private void StartWebRequest(string url)
{
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   request.BeginGetResponse(new AsyncCallback(FinishWebRequest), request);
}

private void FinishWebRequest(IAsyncResult result)
{
   HttpWebResponse response = (result.AsyncState as HttpWebRequest).EndGetResponse(result) as HttpWebResponse;
}

由于文本框值的交叉线程，但这是wpf应用程序，我会重新标记它，顺便说一句，您可以像这样使用webclient

Because of chross thread of textbox'value,But this is wpf application i will retag this, btw you can use webclient like

 private void tbWord_TextChanged(object sender, TextChangedEventArgs e)
    {
        WebClient wc = new WebClient();
        wc.DownloadStringCompleted += HttpsCompleted;
        wc.DownloadStringAsync(new Uri("http://en.wikipedia.org/w/api.php?action=opensearch&search=" + tbWord.Text)); 
    }
    private void HttpsCompleted(object sender, DownloadStringCompletedEventArgs e)
    {
        if (e.Error == null)
        {

             //do what ever 
             //with using e.Result
        }
    } 

这篇关于HttpWebRequest.BeginGetResponse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！