Scroll to selected item in NavigationView UWP

Question

I need to Scroll NavigationView to its SelectedItem . In which I tried below methods one with TryMoveFocusAsync and another by tring to get ScrollViewer through parent of the SelectedItem from SelectionChanged event. But, the parent seems to be null.

Note: NavigationView doesn't have ScrollIntoView like ListView

1st Method

   private async void OnSelectionChanged(
         NavigationView sender, NavigationViewSelectionChangedEventArgs args)
   {
        if (args.SelectedItem is NavigationViewItem item)
        {
           FocusManager.TryFocusAsync(
                    sender.SelectedItem as DependencyObject,
                    FocusState.Pointer);
           ViewModel.NavigateTo(item.Name);
         }
         UpdateBackButton();
   }

2nd Method

   private async void OnSelectionChanged(
        NavigationView sender, NavigationViewSelectionChangedEventArgs args)

(args.SelectedItem as NavigationViewItem).Parent returns null.

Is there a way to scroll the NavigationViewMenuItem to its selected index?

Answer 1

Because the ScrollIntoView convenience method is not available outside of ListView it is a bit more work to get this done. First we need to write a helper method that finds the parent of a DependencyObject using the VisualTreeHelper :

private T FindParentOfType<T>(DependencyObject item)
{
    while (item != null)
    {
        item = VisualTreeHelper.GetParent(item);
        if (item is T expectedParent)
        {
            return expectedParent;
        }
    }
    return default;
}

Now using this, we first find the ScrollViewer (which should be a grand-parent of the NavigationViewItem ):

var scrollViewer = FindParentOfType<ScrollViewer>(item);

We now need to find out the position of this menu item within the scroll viewer, which can be done using TransformToVisual and TransformPoint . Knowing this vertical location we can now scroll to it using ScrollViewer.ChangeView method:

if (scrollViewer != null)
{
    var transform = 
         item.TransformToVisual(scrollViewer)
             .TransformPoint(new Point(0,0));
    scrollViewer.ChangeView(null, transform.Y, null);
}