Getting tapped view's ancestor by type

App.xaml.cs

namespace MyApp
{
    public class App : Application
    {
        // ...
        
        public void OnSelectorTapped(object sender, EventArgs eventArgs)
        {
            var tappedElement = sender as Element;
            
            if (tappedElement == null)
            {
                return;
            }

            NextPrevDateSelector tappedSelector = null;
            Element parent = tappedElement.Parent;

            while (parent != null)
            {
                if (parent is NextPrevDateSelector)
                {
                    tappedSelector = parent as NextPrevDateSelector;
                    break;
                }

                parent = parent.Parent;
            }

            if (tappedSelector != null)
            {
                // Hopefully, if ControlTemplate + ContentView have wired up their respective
                // layouts and views correctly, it will hit this line!
                
                tappedSelector.NextDaySelected.Invoke();
                // or
                tappedSelector.PreviousDaySelected.Invoke();
                
                // or if you need a command
                object commandParameter = "command parameter if you need one, otherwise null";
                
                if (tappedSelector.SomeCommand.CanExecute(commandParameter))
                {
                    tappedSelector.SomeCommand.Execute(commandParameter);
                }
                
                // Check tappedElement in order to determine if you need next or previous day.
                // You should find a way somehow to differentiate between next and previous views.
            }
        }
    }
}