异步 WebRequest 超时 Windows Phone 7

Question

我想知道 Windows Phone7 上 HttpWebRequest 超时的“正确”方法是什么？

我一直在阅读有关 ThreadPool.RegisterWaitForSingleObject() 的内容，但这不能用作 WaitHandles 在运行时抛出未实现的异常。

我也一直在研究 ManualReset 事件，但是 A）没有正确理解它们，B）不明白阻塞调用线程如何成为实现异步请求超时的可接受方法。

这是我现有的代码，没有超时，有人可以告诉我如何为此添加超时吗？

public static void Get(Uri requestUri, HttpResponseReceived httpResponseReceivedCallback, ICredentials credentials, object userState, bool getResponseAsString = true, bool getResponseAsBytes = false)
                {
                    var httpWebRequest = (HttpWebRequest)WebRequest.Create(requestUri);

                    httpWebRequest.Method = "GET";
                    httpWebRequest.Credentials = credentials;

                    var httpClientRequestState = new JsonHttpClientRequestState(null, userState, httpResponseReceivedCallback, httpWebRequest, getResponseAsString, getResponseAsBytes);

                    httpWebRequest.BeginGetResponse(ResponseReceived, httpClientRequestState);
                }

private static void ResponseReceived(IAsyncResult asyncResult)
{
      var httpClientRequestState = asyncResult.AsyncState as JsonHttpClientRequestState;

       Debug.Assert(httpClientRequestState != null, "httpClientRequestState cannot be null. Fatal error.");

       try
       {
           var webResponse  = (HttpWebResponse)httpClientRequestState.HttpWebRequest.EndGetResponse(asyncResult);

       }
}

Answer 1

C# 的基本异步超时模式：

public static T SafeLimex<T>(Func<T> F, int Timeout, out bool Completed)   
   {
       var iar = F.BeginInvoke(null, new object());
       if (iar.AsyncWaitHandle.WaitOne(Timeout))
       {
           Completed = true;
           return F.EndInvoke(iar);
       }
         F.EndInvoke(iar); //not calling EndInvoke will result in a memory leak
         Completed = false;
       return default(T);
   } 

不确定这是否适用于 Windows Phone 7。
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