LINQ to XML vs XPath的簡單效能測試

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

using System.Xml.Linq;

using System.Diagnostics;

using System.Xml.XPath;

using System.Xml;

namespace TestXmlPerformance

{

    class Program

    {

        static void GenSampleXml()

        {

            StringBuilder sb = new StringBuilder();

            sb.Append("<root>");

            Random rnd = new Random();

            for (int i = 0; i < 20000; i++)

            {

                sb.AppendFormat("<pack id=\"{0}\">", i);

                for (int j = 0; j < 100; j++)

                    sb.AppendFormat("<item model=\"{0}\" />",

                        rnd.Next(20));

                sb.Append("</pack>");

            }

            sb.Append("</root>");

            File.WriteAllText(".\\Sample.xml", sb.ToString());

        }

        static void Main(string[] args)

        {

            //GenSampleXml();

            {

                Stopwatch sw = new Stopwatch();

                sw.Start();

                XDocument xd = XDocument.Load(".\\Sample.xml");

                var q = from o in xd.Descendants("item")

                        where o.Attribute("model").Value == "7"

                        select o;

                Console.WriteLine(q.Count());

                sw.Stop();

                Console.WriteLine("Test 1: {0}ms", 

                    sw.ElapsedMilliseconds);

            }

            {

                Stopwatch sw = new Stopwatch();

                sw.Start();

                XDocument xd = XDocument.Load(".\\Sample.xml");

                Console.WriteLine(

                    xd.XPathSelectElements("root/pack/item[@model='7']")

                    .Count()

                );

                sw.Stop();

                Console.WriteLine("Test 2: {0}ms", 

                    sw.ElapsedMilliseconds);

            }

            {

                Stopwatch sw = new Stopwatch();

                sw.Start();

                XmlDocument xd = new XmlDocument();

                xd.Load(".\\Sample.xml");

                Console.WriteLine(

                    xd.DocumentElement

                    .SelectNodes("pack/item[@model='7']").Count

                );

                sw.Stop();

                Console.WriteLine("Test 3: {0}ms", 

                    sw.ElapsedMilliseconds);

            }

            Console.Read();

        }

    }

}