image tirgger fade

FadeTriggerAction.cs

public class FadeTriggerAction : TriggerAction<VisualElement>
{
    public FadeTriggerAction() {}

    public int StartsFrom { set; get; }

    protected override void Invoke (VisualElement visual)
    {
        visual.Animate("", new Animation( (d)=>{
            var val = StartsFrom == 0 ? d : 1-d;
            visual.Opacity = val;

        }),
            length:1000, // milliseconds
            easing: Easing.Linear);
    }
}

imagetrigger.cs

Image image = new Image ();
image.Triggers.Add(new Trigger(typeof(Image)) {
    Property = Image.SourceProperty,
    EnterActions = {
        new FadeTriggerAction() {
            StartsFrom = 1
        }
    },
    ExitActions = {
        new FadeTriggerAction() {
            StartsFrom = 0
        }
    }
});