c#中带头（声明）的xml（封装）生成

XmlDocument downLoadFilexml = new XmlDocument();
XmlElement root = null;
XmlElement kisokChild = null;
//生成xml的头
XmlNode xmlnode= downLoadFilexml.CreateXmlDeclaration("1.0", "utf-8", null);
downLoadFilexml.AppendChild(xmlnode);
root = downLoadFilexml.CreateElement("test");
root.SetAttribute("Guid",“1”);
root.SetAttribute("BuildID","0");
downLoadFilexml.AppendChild(root);
kisokChild = downLoadFilexml.CreateElement("testChild");
kisokChild.SetAttribute("Interval","111");
root.AppendChild(kisokChild);
Response.Write(downLoadFilexml.OuterXml);
Response.End();