Take a look at the image on the right. The top two are just sitting there, while the bottom Button (in this case it’s really just a Border) is animating a shimmer.
The technique simply to animate the offset of a linear gradient that is tilted and applied to the border. It’s crazy easy when you see how I do it.
If there’s a trick, it’s accessing the correct gradient stop. Here’s that syntax:
The other trick is realizing that the gradient stop collection is zero-based. That might get you, too. And they are sorted based on ordinal XAML position and not Offset reference.