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