How to get desired height of WPF UI element with current height of 0?

Question

My ultimate goal is to animate the change in size between two UserControls. The way that I have attempted to achieve this has produced one major problem.

I start wit

Answer 1

Maybe it's easier to animate the LayoutTransform.ScaleY of your target from 0 to 1, because desired height is always 1 and no extra control is needed.