SimplePage.xaml

<dxwui:NavigationPage x:Class="Hamburger.SimplePage"
      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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:Hamburger"
      mc:Ignorable="d" >

    <Grid>
        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center" >
            <TextBlock Text="The menu is hidden" HorizontalAlignment="Center" />
            <Button Content="Show menu"
                    Command="{Binding Path=ToggleViewStateCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type dxwui:HamburgerMenu}}}"/>
        </StackPanel>
    </Grid>
</dxwui:NavigationPage>