private void MainGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var item = MainGrid.SelectedItem;
var itemContainer = MainGrid.ContainerFromItem(item);
Visual visual;
Rectangle rect = FindElementInVisualTree <Rectangle>(itemContainer);
visual = ElementCompositionPreview.GetElementVisual(rect);
var growAnim = visual.Compositor.CreateVector3KeyFrameAnimation();
growAnim.InsertKeyFrame(0.6f, new Vector3(x: 6f, y: 4f, z: 4f));
growAnim.InsertKeyFrame(1.0f, new Vector3(x: 1f, y: 1f, z: 1f));
growAnim.Duration = TimeSpan.FromMilliseconds(2000);
visual.StartAnimation("Scale", growAnim);
}