WPF PageFunction Object

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 WPF.PageBasedApplication
{
    /// <summary>
    /// Interaction logic for HomePage.xaml
    /// </summary>
    public partial class HomePage : Page
    {
        public HomePage()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            //Create instance of PageFunction
            PageFunction apage = new PageFunction();
            //Attach the Return EventHandler to Handle ReturnEventAgrs passed from PageFunction            
            apage.Return += new ReturnEventHandler<object>(apage_Return);
            
            //Navigate to Page Function
            NavigationService.Navigate(apage);
        }

        /// <summary>
        /// Return EventHanlder Method to ReturnEventAgrs passed from PageFunction
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void apage_Return(object sender, ReturnEventArgs<Object> e)
        {
            //Display the Items selected
            List<string> selectedItems = (List<string>)e.Result;
            foreach (string item in selectedItems)
            {
                listBox1.Items.Add(item);
            }
        }
    }
}