HttpClient发布数据失败 [英] HttpClient Post Data Failed

问题描述

我正在创建一个Metro应用程序，它向Web服务器发出HTTP Post请求以获取XML数据，   最初
我使用相同的代码成功登录到Web服务器然后我发出多个Post Request来检索其他数据，但调用从未完成：

        private async Task<string> PostData(string baseUrl, string data)
        {
            string ret = string.Empty;
            HttpClientHandler handler = new HttpClientHandler();
            handler.AllowAutoRedirect = false;
            handler.UseDefaultCredentials = true;
            handler.MaxRequestContentBufferSize = 20000;


            var client = new HttpClient(handler);
            //set RequestHeader (HTTP_USER_AGENT)
            client.DefaultRequestHeaders.Add("user-agent",
                "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)");

            var httpRM = new HttpResponseMessage();

            string useUrl = baseUrl;


            if (Type == PostTypeEnum.Post)
            {
                var content = new StringContent(data);
                try
                {
                    httpRM = await client.PostAsync(useUrl, content);
                }
                catch (Exception ex)
                {
                    Debug.WriteLine(ex.Message);
                    throw;
                }
            }
            else if (Type == PostTypeEnum.Get)
            {
                client.DefaultRequestHeaders.Add("Content-Type",
                    "application/x-www-form-urlencoded");
                if (data.Length > 0)
                    useUrl += "?" + data;

                httpRM = await client.GetAsync(useUrl);
            }

            httpRM.EnsureSuccessStatusCode();


            if (httpRM.IsSuccessStatusCode)
            {
                byte[] response = await httpRM.Content.ReadAsByteArrayAsync();
                ret = new UTF8Encoding().GetString(response, 0, response.Length);
            }
            else
            {
                Debug.WriteLine("ATTENTION ! " + httpRM.StatusCode.ToString());
            }

            return ret;
        }

       

推荐答案

嗨Amr，

如果没有完整的代码，这不是一个可以轻松调试的东西。 不过，我可以给你一些提示：

Without complete code this is not something that can easily be debugged.  However, I can give you some tips:

1. 只创建一个HttpClient并在全局级别使用它。 不要每次都重新创建。

1.  Only create one HttpClient and use it at a global level.  Don't recreate each time.

2. 然后序列化您对HttpClient的调用，这样您就可以进行相同的连接（不要再进行另一次异步调用，直到前一次成功）。

2.  Then serialize your calls to the HttpClient so you can you the same connection (don't make another async call until  the previous succeeds).

3.  system.net跟踪将帮助您了解正在发生的事情： 
http://blogs.msdn.com/b/jpsanders/archive/2011/12/16/how-to-take-a-system-net-trace-from-metro- style-applications-developer-preview.aspx

3.  A system.net trace will help you see what is going on:  http://blogs.msdn.com/b/jpsanders/archive/2011/12/16/how-to-take-a-system-net-trace-from-metro-style-applications-developer-preview.aspx

-Jeff

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