using System;

using System.Xml.XPath;

using System.IO;

public class Program

{

    static string xml = @"

        <tops>

          <top id=""1"" value=""test-1"" />

          <top id=""2"" value=""test-2"" />

        </tops>

    ";

    public static void Main()

    {

        using (StringReader sr = new StringReader(xml))

        {

            XPathDocument d = new XPathDocument(sr);

            foreach (XPathNavigator n in d.CreateNavigator().Select("//tops/top"))

            {

                var idValue = n.GetAttribute("id", "");

                Console.WriteLine("----");

                Console.WriteLine(idValue);

            }

        }

    }

}