WinUi 3 How to fix NavigationView expanding footer item behaviour

Question

The NavigationView expanding footer item behaviour in WinUi 3 is bugged. The footer panel is not resized when an item is expanded and part of the footer is not visible (you can scrool the footer panel).

Answer 1

Add events to NavigationView

<NavigationView
    ...
    Collapsed="NavigationViewControl_Collapsed"
    Expanding="NavigationViewControl_Expanding"
    ... 
>

To redraw NavigationView you need to change it's layout or the window size. I have found that changing the margin is the least invasive:

private void NavigationViewControl_Expanding(NavigationView sender, NavigationViewItemExpandingEventArgs args)
{
    /* To fix NavigationView footer menu item expanding behaviour */
    var item = args.ExpandingItem as NavigationViewItem;
    if(sender.FooterMenuItems.Contains(item))
    {
        if(sender.Margin.Bottom > 0)
        {
            sender.Margin = new(0, 0, 0, 0);
        }
        else
        {
            sender.Margin = new(0, 0, 0, 1);
        }            
    }
}

private void NavigationViewControl_Collapsed(NavigationView sender, NavigationViewItemCollapsedEventArgs args)
{
    /* To fix NavigationView footer menu item expanding behaviour */
    var item = args.CollapsedItem as NavigationViewItem;
    if (sender.FooterMenuItems.Contains(item))
    {
        if (sender.Margin.Bottom > 0)
        {
            sender.Margin = new(0, 0, 0, 0);
        }
        else
        {
            sender.Margin = new(0, 0, 0, 1);
        }
    }
}