private static XPathNavigator GetNavigator(string query )
        {
            try
            {
XmlDocument xmlDox = new XmlDocument();
xmlDocument.Load(pathHere);
                XPathNavigator nav = xmlDoc.CreateNavigator();
                // Doing the select on the config file to get the location of the query
                XPathNodeIterator iterator = nav.Select(query);
                // Starting the interator by calling for the first time to MoveNext
                bool doesPathExistsInXmlFile = iterator.MoveNext();
                // Checking if the query exists in config file.
                if (doesPathExistsInXmlFile )
                {
                    // returning the navigator
                    return (iterator.Current);
                }
                else
                {
                    return null;
                }
            }
            catch (Exception ex)
            {
                throw (ex);
            }
        }

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Xml;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class time : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Expires = -1;
        string s = Request.QueryString;
        bool flag = false;
        XmlTextReader xtr = new XmlTextReader(Request.PhysicalApplicationPath+"XMLFile.xml");
        string FullStr = "";
        while (xtr.Read())
        {
            if (xtr.IsStartElement("GuestNum") == true && s == xtr.GetAttribute("num"))
            {
                flag = true;
                FullStr += xtr.GetAttribute("num")+"<br/>";
            }
      
                if (flag==true && xtr.IsStartElement("name"))
                {
                    FullStr += "name:" + xtr.ReadInnerXml()+"<br/>";
                }
                if (flag == true && xtr.IsStartElement("phone"))
                {
                    FullStr += xtr.GetAttribute("type") + ":" + xtr.ReadInnerXml() + "<br/>";
                    
                }
                if (flag == true && xtr.IsStartElement("MSN"))
                {
                    FullStr += xtr.ReadInnerXml() + "<br/>";
                }
                if (flag == true && xtr.IsStartElement("disc"))
                {
                    FullStr += xtr.ReadInnerXml() + "<br/>";
                }

                if (xtr.Name == "GuestNum" && xtr.NodeType == XmlNodeType.EndElement)
                {
                    flag = false;
                }
        }
       
        if(s!="")
        Response.Write(FullStr);
        Response.End();
    }
}