HttpWebRequest 返回BadRequest(400) 同时返回Response

今天用Fiddler分析安卓APP的一个登陆功能的时候，账号和密码错误会返回相应的消息，并且状态码是400。

正常用法：

         /// <summary>
         /// 读取返回的内容
         /// </summary>
         /// <param name="asyncresult"></param>
         private void ReadCallBack(IAsyncResult asyncresult)
         {
             String result = String.Empty;
             try
             {
                 HttpWebRequest myrequest = (HttpWebRequest)asyncresult.AsyncState;
                 HttpWebResponse response = (HttpWebResponse)myrequest.EndGetResponse(asyncresult);

                 //读取返回对象
                 Stream responseStream = response.GetResponseStream();

                 using (var render = new StreamReader(responseStream, Encoding.UTF8))
                 {
                     result = render.ReadToEnd();
                     render.Close();
                 }
             }
             catch (Exception ex)
             {

                 Console.WriteLine("出现异常：" + ex.Message);
             }
             //处理返回消息
             if (Handler != null)
                 Handler(result);
         }

当执行GetResponseStream就抛出异常了，异常提示是BadRequest.

要想获取400返回的信息，需要对catch部分做特殊处理。

添加catch代码：

 catch (Exception ex)
 {
     using (WebResponse response = e.Response)
         {
             HttpWebResponse httpResponse = (HttpWebResponse)response;
                 using (Stream data = response.GetResponseStream()){
                     using (var reader = new StreamReader(data))
                     {
                              string text = reader.ReadToEnd();
                              Console.WriteLine(text);
                     }
         　　　　}
          }
 }

这样就可以获取到400返回的消息了。

stackoverflow问题链接：

http://stackoverflow.com/questions/692342/net-httpwebrequest-getresponse-raises-exception-when-http-status-code-400-ba

http://stackoverflow.com/questions/11660947/httpwebrequest-getresponse-throws-bad-request-400-error