HOW to load a page with window in a frame

<window x:class="Mydemo.MainWindow" xmlns:x="#unknown">
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="300" Width="300">
    <grid>
        <Frame Name="sdkFrame" Background="WhiteSmoke" Source="Page1.xaml" NavigationUIVisibility="Visible" />
    </grid>
</window>

public MainWindow()
        {
            InitializeComponent();
            this.sdkFrame.Navigate(new Uri("Page1.xaml", UriKind.Relative));

        }