C#创建XML

//更新时写入XML        protected void GridView2_RowUpdated(object sender, GridViewUpdatedEventArgs e)        {            XmlDocument xmldoc = new XmlDocument();            XmlDeclaration xmldecl = xmldoc.CreateXmlDeclaration("1.0", "GBK", null);   //创建段落申明            xmldoc.AppendChild(xmldecl);            XmlElement  root= xmldoc.CreateElement("sysconfig");            string CmdStr="select * from sysconfig";            OleDbDataReader Reader=AccessHelper.ExecuteReader(AccessHelper.ConnectionString, CmdStr, null);            while (Reader.Read()) {                XmlElement Element = xmldoc.CreateElement("Item");   //创建第一层                XmlElement c1 = xmldoc.CreateElement("ID");                XmlElement c2 = xmldoc.CreateElement("参数");                XmlElement c3 = xmldoc.CreateElement("值");                c1.InnerText = Reader["ID"].ToString();                c2.InnerText = Reader["参数"].ToString();                c3.InnerText = Reader["值"].ToString();                Element.AppendChild(c1);                Element.AppendChild(c2);                Element.AppendChild(c3);                root.AppendChild(Element);            }            xmldoc.AppendChild(root);        }