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copied!<p>I'm making asynchronous requests with <a href="http://msdn.microsoft.com/en-us/library/system.net.webrequest.begingetresponse.aspx" rel="nofollow">WebRequest.BeginGetResponse</a> to download files from a server. All works nice but I want to download no more of 5 files at the same time. In Java I would use a fixed thread pool but I don't know how to do the same in C#. Any ideas?</p> <pre><code>class HttpFetcher { public void MakeRequest(Uri uri) { WebRequest request = WebRequest.Create(uri); request.Proxy = null; RequestState requestState = new RequestState(); requestState.Request = request; IAsyncResult result = (IAsyncResult) request.BeginGetResponse(new AsyncCallback(ResponseCallback), requestState); ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(TimeOutCallback), request, 1000, true); } private void ResponseCallback(IAsyncResult result) { try { RequestState requestState = (RequestState)result.AsyncState; WebRequest request = requestState.Request; requestState.Response = request.EndGetResponse(result); Stream responseStream = requestState.Response.GetResponseStream(); requestState.ResponseStream = responseStream; IAsyncResult asynchronousResultRead = responseStream.BeginRead(requestState.BufferRead, 0, 1024, new AsyncCallback(ReadCallback), requestState); } catch (Exception ex) { Console.WriteLine("Exception raised!"); Console.WriteLine("Message : {0}", ex.Message); RequestState state = (RequestState)result.AsyncState; if (state.Response != null) state.Response.Close(); } } private void ReadCallback(IAsyncResult result) { try { RequestState requestState = (RequestState)result.AsyncState; Stream responseStream = requestState.ResponseStream; int bytesRead = responseStream.EndRead(result); if (bytesRead > 0) { requestState.RequestData.Append(Encoding.ASCII.GetString(requestState.BufferRead, 0, bytesRead)); IAsyncResult asynchronousResult = responseStream.BeginRead(requestState.BufferRead, 0, 1024, new AsyncCallback(ReadCallback), requestState); } else { Console.WriteLine("\nThe HTML page Contents are: "); if (requestState.RequestData.Length > 1) { string sringContent; sringContent = requestState.RequestData.ToString(); //Console.WriteLine(sringContent); } Console.WriteLine("\nPress 'Enter' key to continue........"); responseStream.Close(); } } catch (WebException e) { Console.WriteLine("WebException raised!"); Console.WriteLine("\n{0}", e.Message); Console.WriteLine("\n{0}", e.Status); } catch (Exception e) { Console.WriteLine("Exception raised!"); Console.WriteLine("Source : {0}", e.Source); Console.WriteLine("Message : {0}", e.Message); } } private void TimeOutCallback(object state, bool timedOut) { if (timedOut) { WebRequest request = (WebRequest)state; if (state != null) { request.Abort(); } } } } </code></pre>

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