private void AnimateBackdrop(bool show)
{
if (Container == null)
{
throw new NotImplementedException($"'{nameof(Container)}' must be implemented");
}
if (UseBackdrop && Backdrop == null)
{
throw new NotImplementedException($"'{nameof(Backdrop)}' must be implemented when '{nameof(UseBackdrop)}' is true");
}
var opacity = show ? 0.6 : 0;
if (show || Backdrop.Visibility == Visibility.Hidden)
{
Backdrop.Visibility = Visibility.Visible;
}
var backdropAnimation = new DoubleAnimation(Backdrop.Opacity, opacity, TimeSpan.FromMilliseconds(200));
if (!show)
{
backdropAnimation.Completed += (sender, args) => Backdrop.Visibility = Visibility.Hidden;
}
Backdrop.BeginAnimation(UIElement.OpacityProperty, backdropAnimation);
}