HTTP Get

try
            { 
                string xml = BuildXml(Para22);
                System.Net.HttpWebRequest request;
                string ss = EncodeBase64(xml); 
                ss = HttpUtility.UrlEncode(ss);
                string url = textBoxExtend11.Text + "ZTYCode.ashx?xmlmsg=" + ss;
                request = (System.Net.HttpWebRequest)WebRequest.Create(url);
                request.Method = "GET";
                request.ContentType = "text/plain";
                System.Net.HttpWebResponse response;
                StreamReader sr = null;
                response = (System.Net.HttpWebResponse)request.GetResponse();
                sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                XmlDocument xmlDoc = new XmlDocument();
                xmlDoc.InnerXml = sr.ReadToEnd().Trim();
                XmlNode doc = xmlDoc.SelectSingleNode("response");
                string DesXML = DecodeBase64(doc.SelectSingleNode("body").InnerText.ToString());
                textBoxExtend9.Text = "";
                textBoxExtend9.Text = DesXML;
            }
            catch (Exception ex)
            {
                FrmShowMessage.Show(ex.Message);
            }