创建XML

//创建XML

XElement xelement = new XElement("request",

                  new XElement("head",

                  new XElement("msgId", System.Guid.NewGuid().ToString()),//

                  new XElement("timeStamp", string.Format("{0:yyyyMMddHHmmssfffff}", DateTime.Now)),

                  new XElement("session", ""),

                  new XElement("userCode", "")),//

              new XElement("body",

                  new XElement("vehicle",

                          new XElement("brandName", brandName))));//车型名称

            string RequestCarsXML = string.Format("<?xml version=\"1.0\" encoding=\"UTF-8\"?>{0}{1}", System.Environment.NewLine, xelement.ToString());