MainPage_SubPage.xaml

<dxwui:NavigationPage x:Class="Hamburger.MainPage_SubPage"
        xmlns:dxwui="http://schemas.devexpress.com/winfx/2008/xaml/windowsui"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Hamburger"
        mc:Ignorable="d"
        d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Text="SubMenu" />

    </Grid>
</dxwui:NavigationPage>