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

You can put the content you want the size of into a Canvas with ClipToBound="True". Then you can manipulate the size of the Canvas and yet the size of the content inside the Canvas will always be its full desired size.