How can I exit the window while press the Esc key

When I on the windows page I want to exit this window,how can I do it in code.

The following code do that as example.

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.Shapes;

namespace ?????.Views.Configuration
{
/// <summary>
/// Interaction logic for About.xaml
/// </summary>
public partial class About : Window
{
public About()
{
InitializeComponent();
PreviewKeyDown += new KeyEventHandler(CloseOnEscape);
}

private void CloseOnEscape(object sender, KeyEventArgs e)
{
if (e.Key == System.Windows.Input.Key.Escape)
Close();
}
}
}