using System;

using System.Linq;

using System.Collections.Generic;

using System.Xml;

using System.Xml.Linq;

using System.Xml.Serialization;

public class Program

{

    public static void Main()

    {

        string xml = @"<People>

            <Continent>Asia</Continent>

            <TimeZone>Hong Kong Standard Time</TimeZone>

            <Person>

                <FirstName>Joe</FirstName>

                <LastName>Stevenson</LastName>

            </Person>

            <Person>

                <FirstName>Joe</FirstName>

                <LastName>Hancock</LastName>

            </Person>

            <Person>

                <FirstName>Kirby</FirstName>

                <LastName>Stevenson</LastName>

            </Person>

        </People>";

        string trimmedFirstName = "Joe";

        string trimmedLastName = "Stevenson";

        XDocument convertedPayload = XDocument.Parse(xml);

        List<XElement> peopleChildren = convertedPayload.Descendants("Person")

            .Where(a => a.Value.Contains(trimmedFirstName)

                   && a.Value.Contains(trimmedLastName))

            .ToList();

        Console.WriteLine(peopleChildren.Count());

        //using System.IO.StringWriter sw = new System.IO.StringWriter();

        //convertedPayload.Save(sw);

        using System.IO.StringWriter sw = new System.IO.StringWriter();

        using XmlTextWriter xmlTextWriter = new XmlTextWriter(sw) { Formatting = Formatting.Indented };

​

        XmlSerializer serializer = new XmlSerializer(peopleChildren.GetType());

        serializer.Serialize(sw, peopleChildren);

        Console.WriteLine(sw.ToString());

    }

}