using System;

using System.Linq;

using System.Xml;                   

using System.Xml.Linq;

using System.Collections; 

using System.Collections.Generic;

using System.Data;

using System.Data.DataSetExtensions;

using System.Data.Linq;

using System.Text;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string input = @"<root>

    <child1>

        Value1

    </child1>

    <child2>

            <child3>

                Value2

            </child3>

            <child4>

                    <child5>

                        Value1

                    </child5>

            </child4>

    </child2>

    <child6>

        Value1

    </child6>

</root>";

        XDocument doc = XDocument.Parse(input);     

        doc.Descendants()

           .Where(x=> (!x.HasElements &&((string)x.Value).Trim() == "Value1")

                  || (x.Attribute("value") != null && x.Attribute("value").Value == "Value1"))

           .Count().Dump();  

    }

}

​

​