// Animate the drop down menu
protected override async void OnDropDownOpened(object e)
{
if (_TranslationElement != null)
{
// Pick the animation direction depending on the current position
int?count = ((ItemsSource as ICollection)?.Count ?? (ItemsSource as IEnumerable)?.Count())
?? Items?.Count;
bool down = count == null || ((SelectedIndex < 1 || SelectedIndex <= count / 2) &&
!(count == 2 && SelectedIndex == 1));
float start = down ? -16 : 16;
_TranslationElement.Animation().Offset(Axis.Y, start);
// Animate using Windows.UI.Composition animations to avoid frame drops
await _TranslationElement.Animation()
.Translation(Axis.Y, start, 0, Easing.CircleEaseOut)
.Duration(250)
.StartAsync();
}
base.OnDropDownOpened(e);
}