Write data to xml file? (Visual Studio 2013,c#)

I am trying to figure out how to write names entered in nameTextBox to an attendees.xml file when checkInButton is clicked. These names should subsequently be displayed with names of other people in the conference room in the inMeetingListBox. Any code samples would be greatly appreciated. Thanks!

Default.aspx:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace ConferenceRoomTracker
{
    public partial class Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void checkInButton_Click(object sender, EventArgs e)
        {
            inMeetingListBox.Items.Add(nameTextBox.Text); 
        }

        protected void checkOutButton_Click(object sender, EventArgs e)
        {
            inMeetingListBox.Items.Remove(inMeetingListBox.SelectedItem);
        }

        protected void clearAllButton_Click(object sender, EventArgs e)
        {
            clearNameList();
        }

        public void clearNameList()
        {
            inMeetingListBox.Items.Clear();

        }


    }
}

attendees.xml:

<?xml version="1.0" encoding="utf-8" ?>
<attendee>
  <name>Jake Jones</name>
  <name>James Harrison</name>
  <name>Thomas Jefferson</name>
  <name>Tim Boylston</name>
</attendee>