อยากทราบวิธีการใช้ C#(wpf) สร้าง xml ได้ยังไงบ้างคะ??...ผู้รู็ช่วยแนะนำหน่อยค่ะ ^^

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WpfApplication1
{
    [Serializable]
    public class QA
    {
        public string question { get; set; }
        public string choice1 { get; set; }
        public string choice2 { get; set; }
        public string choice3 { get; set; }
        public string choice4 { get; set; }

        public QA()
        {

        }

        public QA(string question, string c1, string c2, string c3, string c4)
        {
            this.question = question;
            choice1 = c1;
            choice2 = c2;
            choice3 = c3;
            choice4 = c4;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            List<QA> qa = new List<QA>();
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));
            qa.Add(new QA("q1", "c1", "c2", "c3", "c4"));

            using (var sw = new System.IO.StreamWriter(@"c:\test.xml"))
            {
                var serializer = new System.Xml.Serialization.XmlSerializer(typeof(List<QA>));
                serializer.Serialize(sw, qa);
            }
        }
    }
}