Xamarin.Forms-Samples/Xamarin.Forms-Styles/Xamarin Styles/Xamarin_Styles.WinPhone/MainPage.xaml

<winPhone:FormsApplicationPage
    x:Class="Xamarin_Styles.WinPhone.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:winPhone="clr-namespace:Xamarin.Forms.Platform.WinPhone;assembly=Xamarin.Forms.Platform.WP8"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

</winPhone:FormsApplicationPage>