WPF C#

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="NavigationApplication" Height="300" Width="500"
    >
 

//File:Window.xaml.cs
using System;
using System.Collections.Generic;
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 NavigationApplication
{
    public partial class StartupWindow : System.Windows.Navigation.NavigationWindow
    {
        public StartupWindow()
        {
            InitializeComponent();
            this.Content = new Menu();
        }
    }
}