C# HttpWebRequest 请求返回 The remote server returned an error: (400) Bad Request.

可以看下他的响应Body

catch (WebException ex)
            {
                if (ex.Status == WebExceptionStatus.ProtocolError)
                {
                    HttpWebResponse err = ex.Response as HttpWebResponse;
                    if (err != null)
                    {
                        string htmlResponse = new StreamReader(err.GetResponseStream()).ReadToEnd();
                        string txtResults = string.Format("{0} {1}", err.StatusDescription, htmlResponse);
                        return txtResults;
                    }
                }
                return ex.Message;
            }