.NET线程 - HttpWebRequest的BeginGetResponse +的AutoResetEvent [英] .NET Threading - HttpWebRequest BeginGetResponse + AutoResetEvent

问题描述

我想知道这两个之间的办法是更好地执行？
我需要创建一个Web请求，可以200毫秒到5秒之间。我需要的HTML响应进行 - 因此需要在主线程阻塞

第一种方法

 字符串的GetResponse（）
 {
 
 HttpWebRequest的要求=（HttpWebRequest的）HttpWebRequest.Create（URL）; 
 IAsyncResult的结果= request.BeginGetResponse（NULL，NULL）; 
 
使用（HttpWebResponse的HttpResponse =（HttpWebResponse）request.EndGetResponse（结果））使用（流数据流= httpResponse.GetResponseStream（））
 {
 $ B {
 $ b StreamReader的读者=新的StreamReader（数据流）; 
响应= reader.ReadToEnd（）; 
} 
} 
  

第二种方法

 字符串响应=的String.Empty; 
的AutoResetEvent的WaitHandle = NULL; 
无效的GetResponse（字符串URL）
 {
的WaitHandle =新的AutoResetEvent（假）; 
试
 {
 HttpWebRequest的要求=（HttpWebRequest的）HttpWebRequest.Create（URL）; 
 IAsyncResult的asyncResult = request.BeginGetResponse（回调，请求）; 
 
 waitHandle.WaitOne（）; 
} 
赶上{} 
终于
 {
 waitHandle.Close（）; 
} 
} 
 
的回调（IAsyncResult的asyncResult）
 {
 
 HttpWebRequest的要求=（HttpWebRequest的）asyncResult.AsyncState; 
试
 {使用（HttpWebResponse的HttpResponse =（HttpWebResponse）request.EndGetResponse（asyncResult））
 {
如果（httpResponse.StatusCode == HttpStatusCode.OK）$ 
 b $ b {使用
（流数据流= httpResponse.GetResponseStream（））
 {
 StreamReader的读者=新的StreamReader（数据流）; 
响应= reader.ReadToEnd（）; 
} 
} 
} 
} 
赶上{} 
终于
 {
 waitHandle.Set（）; 
} 
} 
  

解决方案

为什么不执行主线程上的Web请求？如果你想在主线程被阻塞，这是迄今为止做到这一点最简单的方法。

I would like to know which approach among the two is a better implementation ? I need to create a web request which can range between 200ms to 5 seconds. I need the html response to proceed - so need to block on the main thread.

First Approach

string GetResponse()
{

    HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
    IAsyncResult result = request.BeginGetResponse(null, null);    

using (HttpWebResponse httpResponse = (HttpWebResponse)request.EndGetResponse(result))
{
    using (Stream dataStream = httpResponse.GetResponseStream())
    {
        StreamReader reader = new StreamReader(dataStream);
        response = reader.ReadToEnd();
    }
}

Second Approach

string response = string.Empty;
AutoResetEvent waitHandle = null;
void GetResponse(string url)
{
    waitHandle = new AutoResetEvent(false);
    try
    {
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
        IAsyncResult asyncResult = request.BeginGetResponse(Callback, request);

        waitHandle.WaitOne();
    }
    catch { }
    finally
    {
        waitHandle.Close();
    }
}

    void Callback(IAsyncResult asyncResult)      
    {           

HttpWebRequest request = (HttpWebRequest)asyncResult.AsyncState;
            try
            {
                using (HttpWebResponse httpResponse = (HttpWebResponse)request.EndGetResponse(asyncResult))
                {
                    if (httpResponse.StatusCode == HttpStatusCode.OK)
                    {
                        using (Stream dataStream = httpResponse.GetResponseStream())
                        {
                            StreamReader reader = new StreamReader(dataStream);
                            response = reader.ReadToEnd();
                        }
                    }
                }
            }
            catch { }
            finally
            {
                waitHandle.Set();
            }
        }

解决方案

Why not execute the web request on the main thread? If you want the main thread to block, this is by far the easiest way to accomplish this.

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