publicvoid CreateLayerKeyframe(Layer layer, double transparency, TimeSpan atTime)
{
var mapView = MapView.Active;
if (mapView != null)
return;
var animation = mapView.Map.Animation;
var layerTrack = animation.Tracks.OfType<LayerTrack>().First(); //There will always be only 1 LayerTrack in the animation.
layerTrack.CreateKeyframe(layer, atTime, true, transparency, ArcGIS.Core.CIM.AnimationTransition.Linear);
}