XmlNode root = xn.FirstChild.FirstChild;
XmlElement xesub1 = doc.CreateElement("image");
xesub1.InnerText = strA;//设置文本节点
root.AppendChild(xesub1);
XmlNode root = xn2.FirstChild;
XmlElement xesub1 = doc.CreateElement("SITENAME");
xesub1.InnerText = strA;//设置文本节点
xn2.InsertBefore(xesub1,xn2.FirstChild);//插入节点