การ select field อื่น จาก dropdownlist รบกวนช่วยแนะนำหน่อยนะคะ จากโค๊ด เราสร้าง DataTable

                    // Create a new WebClient instance.
                    WebClient myWebClient = new WebClient();
                    //myWebClient.Encoding = Encoding.UTF8;

                    // Create a new NameValueCollection instance to hold some custom parameters to be posted to the URL.
                    NameValueCollection myNameValueCollection = new NameValueCollection();

                    
                    string uri = ("http://www.xxx.com/x-hosting/web-service/get-xxx-detail.php");

                        
                    byte[] responseArray = myWebClient.UploadValues(uri, "POST", myNameValueCollection);

                    // Decode and display the response.
                    string returnxml = Encoding.UTF8.GetString(responseArray);


                    DataTable rec = new DataTable();
                    rec.Columns.AddRange(new DataColumn[] { 
                    new DataColumn("id", typeof(string)),
                    new DataColumn("price", typeof(string)),
                    new DataColumn("description", typeof(string))
                          });
            
                    XmlDocument doc = new XmlDocument();
                    doc.LoadXml(returnxml);
                    foreach (XmlNode recNode in doc.GetElementsByTagName("detail"))
                    {

                        DataRow row = rec.Rows.Add(
                        recNode["id"].InnerText,
                        recNode["price"].InnerText,
                        recNode["description"].InnerText);
                       //Response.Write("" + ": " + recNode["id"].InnerText + "<br />");  
                    
                    }


                    dropdownlist.DataSource = rec.DefaultView;
                    dropdownlist.DataValueField = rec.Columns["id"].ToString();
                    dropdownlist.DataTextField = rec.Columns["description"].ToString();
                    dropdownlist.DataBind();
                               
                               
                }


                catch (Exception ex)
                {
                    ErrMSG.Text = "Error," + ex;
                    ErrMSG.ForeColor = Color.Red;

                }