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我正在遍历大量对象（1503）并在我编写的 ServiceProxy 上调用 save 方法。服务代理使用 Silverlight 4 中的新网络堆栈调用 BeginGetRequestStream 以启动将我的对象异步发送到我为保存对象而编写的 azure REST 服务的过程。我使用的 Http 方法是 POST。我知道 HttpWebClient 足够聪明，可以重用 Http 连接，所以我不会同时打开到服务器的 1503 连接。保存工作正常，所有 1503 个对象都保存得非常快。但是，当我再次尝试保存相同的对象时，我希望收到一个禁止的 HttpStatus 代码，因为这些对象已经存在，并且这是我设置我的天蓝色 Web 服务返回的代码。在小对象组上，它按预期工作。然而，

System.Exception ---> System.Exception:Error HRESULT E_FAIL has been returned from a call to a COM component.
at
System.Net.Browser.ClientHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)...

我想知道我是否应该在我忽略的 HttpWebClient 实例上执行某种簿记或维护，这就是导致 http 错误引发异常的原因，但新的保存可以完美地工作。这是我处理错误情况的代码：

private static void SendAncestorResponseCallback(IAsyncResult result)
    {
        var info = (SendAncestorInfo)result.AsyncState;

        try
        {
            var response = info.Request.EndGetResponse(result);
            info.Response = response;
        }
        catch ( Exception ex)
        {
            info.Error = ex;
        }

        info.MainThreadContext.Post(SendAncestorMainThreadCallback, info);
    }
    private static void SendAncestorMainThreadCallback(object state)
    {
        var info = (SendAncestorInfo)state;
        IAncestor origAncestor = info.Content;
        HttpWebResponse response = null;
        if (info.Error != null)
        {
            if ((info.Error as WebException) == null)
            {
                info.Callback(false, origAncestor, null, info.Error);
                return;
            }
            else //get response from WebException
            {
                response = (HttpWebResponse)(info.Error as WebException).Response;
            }
        }
        else  //get response from info.Response
        {
            response = info.Response as HttpWebResponse;
        } 
        if (response.StatusCode == HttpStatusCode.Created || response.StatusCode == HttpStatusCode.Forbidden)
        {
            var stream = response.GetResponseStream();
            using (var reader = new StreamReader(stream))
            {
                IAncestor retAncestor = XMLSerializerHelper.DeserializeObject<Ancestor>(reader.ReadToEnd());
                info.Callback(response.StatusCode == HttpStatusCode.Created, origAncestor, retAncestor, null);        
            }
        }
        else info.Callback(false, origAncestor, null, info.Error);
    }

考虑到 Web 服务是如何编写的，我应该只期望创建或禁止的 http 状态代码，就像我对小组所说的那样。我只是开始收到前面提到的错误这一事实让我觉得我在 HttpWebRequest 对象等方面做错了。任何帮助将不胜感激。谢谢。

--update 这里是生成 HttpWebRequest 的代码：

foreach (IAncestor ancestor in ancestors)
            {
                AncestorViewModel ancestorVM = new AncestorViewModel(ancestor);
                ancestorVM.Status = SaveStatus.Undefined;
                ParsedAncestors.Add(ancestorVM);
                _service.CreateAncestor(UserSrc, ancestor, (success, origAncestor, retAncestor, exception) =>
                    {
                        AncestorViewModel result = ParsedAncestors.First(a => a.Model.IdNo == origAncestor.IdNo);
                        if (exception == null)//web response was either Created or Forbidden
                        {
                            if (success)//Ancestor successfully created
                            {
                                savedAncestors++;
                                SuccessMessage = string.Format("{0} Saved\n", savedAncestors);
                                result.Status = SaveStatus.Saved;
                            }
                            else //Ancestor already existed
                            {
                                conflictAncestors.Add(origAncestor, retAncestor);
                                ConflictMessage = string.Format("{0} Conflicts\n", conflictAncestors.Count);
                                result.Status = SaveStatus.Conflicted;
                            } 
                        }
                        else //Show exception recieved from remote web service
                        {
                            //if (exception as WebException != null)
                            //{
                            //    //if exception is WebException get status code and description
                            //    HttpWebResponse rs = (HttpWebResponse)(exception as WebException).Response;
                            //    Message += string.Format("WebServer returned status code {0}: '{1}'\n", (int)rs.StatusCode, rs.StatusDescription);
                            //}
                            errors.Add(origAncestor, exception);
                            ErrorMessage = string.Format("{0} Errors\n", errors.Count);
                            result.Status = SaveStatus.Error;
                        }
                    });
            }

public void CreateAncestor(string userSrc, IAncestor ancestor, Action<bool, IAncestor, IAncestor, Exception> callback)
    {
        WebRequest.RegisterPrefix("http://", WebRequestCreator.ClientHttp);
        var request = (HttpWebRequest)WebRequest.Create(
            new Uri(string.Format("{0}/{1}/{2}", rootUri, AncestorsRestPoint, userSrc)));
        request.Method = "POST";
        request.ContentType = "application/xml";
        var info = new SendAncestorInfo
        {
            Request = request,
            Callback = callback,
            Content = ancestor,
            MainThreadContext = SynchronizationContext.Current
        };

        request.BeginGetRequestStream(SendAncestorRequestCallback, info);
    }
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