C#的post请求 捕获错误代码的内容

public string Query(string queryString)
        {
            try
            {
                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(AOPResource.LVSRequestURL);
                request.Method = "POST";
                UTF8Encoding encoding = new UTF8Encoding();
                byte[] byteArray = encoding.GetBytes(queryString);

                request.ContentType = "application/x-www-form-urlencoded";
                request.ContentLength = byteArray.Length;

                Stream requestStream = request.GetRequestStream();
                requestStream.Write(byteArray, 0, byteArray.Length);
                WebResponse response = request.GetResponse();
                Stream responseStream = response.GetResponseStream();
                StreamReader sr = new StreamReader(responseStream);

                string result = sr.ReadToEnd();
                requestStream.Close();
                sr.Close();
                responseStream.Close();
                return result;
            }
            catch (WebException e)
            {
                using (WebResponse response = e.Response)
                {
                    HttpWebResponse httpResponse = (HttpWebResponse)response;
                    Console.WriteLine("Error code: {0}", httpResponse.StatusCode);
                    using (Stream data = response.GetResponseStream())
                    using (var reader = new StreamReader(data))
                    {
                        string text = reader.ReadToEnd();
                        throw new Exception(text);
                    }
                }
            }
        }