public MainPage()

        {

            this.InitializeComponent();

            //---< set App Title Bar >---

            // Get the instance of the Title Bar

            var appTitelBar = ApplicationView.GetForCurrentView().TitleBar;

            // Set the color of the Title Bar content

            appTitelBar.BackgroundColor = Colors.Black;

            appTitelBar.ForegroundColor = Colors.White;

            // Set the color of the Title Bar buttons

            appTitelBar.ButtonBackgroundColor = Colors.Black;

            appTitelBar.ButtonForegroundColor = Colors.White;

            ////< hide App Bar >

            var coreTitleBar = CoreApplication.GetCurrentView().TitleBar;

            coreTitleBar.ExtendViewIntoTitleBar = false;

            ////</ hide App Bar >

            //---</ set App Title Bar >---

        }