C# XPATH vs LINQ

Use Xmlreader for parsing xml document.
Create an xml file as show below, but with 10000 contact elements called as “address_xw_n.xml” and make it available in D driver (d:\).

<AddressBook>
  <Contact>
    <Name>Person1</Name>
    <Address1><![CDATA[Number101]]></Address1>
    <Address2><![CDATA[Address501]]></Address2>
    <Zip>50001</Zip>
    <Phone><![CDATA[999991]]></Phone>
 </Contact>
</AddressBook>

The below code demonstrate the time take to query the above created xml file using xpath and LINQ for the Phone element value “999999996“.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Diagnostics;
using System.Xml.Linq;
namespace QueryXML
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch objSW = null;
            String strNormalFilePath;
            strNormalFilePath = @"d:\address_xw_n.xml";
            XmlDocument xmlNDoc;
            xmlNDoc = new XmlDocument();
            XDocument xNDoc;
            objSW = new Stopwatch();

            objSW.Reset();
            objSW.Start();
            //load the xml
            xmlNDoc.Load(strNormalFilePath);
            //xml query using xpath - Normal format
            objSW.Reset();
            objSW.Start();
            XmlNode xmlQNNode = xmlNDoc.SelectSingleNode(
                "/AddressBook/Contact/Phone[contains(text(),'999999996')]");
            //Console.WriteLine(xmlQNNode.Name +
            //  "-" + xmlQNNode.ChildNodes[0].Value);
            objSW.Stop();
            Console.WriteLine("XML query using xpath - Normal format");
            Console.WriteLine("TimeElapsed (Stopwatch float):{0}ms",
                objSW.Elapsed.TotalMilliseconds);
            Console.WriteLine("TimeElapsed (Stopwatch rounded):{0}ms",
                objSW.ElapsedMilliseconds);

            //xml query using LINQ - Normal format
            //Let us not include the conversion of XmlDocument to XDocument
            xNDoc = XDocument.Parse(xmlNDoc.OuterXml);
            objSW.Reset();
            objSW.Start();
            var linqNQuery = from p in
                                 xNDoc.Root.Elements("Contact").Elements("Phone")
                             where p.Value.Contains("999999996") select p;
            /*foreach (XElement e in linqNQuery)
            {
                Console.WriteLine(e.Name+"-"+e.Value);
            }*/
            objSW.Stop();
            Console.WriteLine("XML query using LINQ - Normal format");
            Console.WriteLine("TimeElapsed (Stopwatch float):{0}ms",
                objSW.Elapsed.TotalMilliseconds);
            Console.WriteLine("TimeElapsed (Stopwatch rounded):{0}ms",
                objSW.ElapsedMilliseconds);

            Console.ReadLine();
        }
    }
}

Output:
XML query using xpath - Normal format
TimeElapsed (Stopwatch float):20.0936ms
TimeElapsed (Stopwatch rounded):20ms
XML query using LINQ - Normal format
TimeElapsed (Stopwatch float):0.5082ms
TimeElapsed (Stopwatch rounded):0ms

Rule: Use LINQ for querying xml content.