In case you haven't already noticed Marcie's article on custom DataGridColumns. It's worth taking a look at not only if you want to understand how the HierarGrid works. There, I created the so-called HierarColumn that acts as the container for the child templates and is filled during the ItemDataBound event.
Good job, Marcie!
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in anyway.
© Copyright 2012, Denis Bauer