C# FocusZone

gistfile1.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.System;
using Windows.UI.Core;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace App1
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }
        async void OnKeyDown(object sender, KeyRoutedEventArgs e)
        {
            var isShiftDown = CoreWindow.GetForCurrentThread().GetKeyState(VirtualKey.Shift).HasFlag(CoreVirtualKeyStates.Down);
            if (e.Key == Windows.System.VirtualKey.Up)
            {
                var isFirstControlFocused = FocusManager.FindFirstFocusableElement((DependencyObject)sender) == FocusManager.GetFocusedElement();
                if (!isFirstControlFocused)
                {
                    FocusManager.TryMoveFocus(FocusNavigationDirection.Previous);
                    e.Handled = true;
                }
            }
            else if (e.Key == Windows.System.VirtualKey.Down)
            {
                var isLastControlFocused = FocusManager.FindLastFocusableElement((DependencyObject)sender) == FocusManager.GetFocusedElement();
                if (!isLastControlFocused)
                {
                    FocusManager.TryMoveFocus(FocusNavigationDirection.Next);
                    e.Handled = true;
                }
            } else if (e.Key == Windows.System.VirtualKey.Tab)
            {
                var options = new FindNextElementOptions()
                {
                    ExclusionRect = LayoutInformation.GetLayoutSlot((FrameworkElement)sender),
                };

                var result = FocusManager.FindNextElement(isShiftDown ? FocusNavigationDirection.Up : FocusNavigationDirection.Down, options);
                await FocusManager.TryFocusAsync(result, FocusState.Programmatic);
                e.Handled = true;
            }
        }
    }

}