列出xml节点遍历的方法，并写出一段脚本

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml;
using System.Text;
// 运用xmlReader解析文件
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

StringBuilder s = new StringBuilder("");
XmlReader read = new XmlTextReader(Server.MapPath("App_Data/servlet.xml"));
try{
// 开始读取文件
while (read.Read()) {
switch (read.NodeType) {
case XmlNodeType.XmlDeclaration: // 如果是文档声明
s.Append("<?"+read.Value + "?>\n");