I wanted to have a dynamic form that had hiding/showing input elements, and still contained validation that was extended from my data annotated models. I followed xhalent’s blog post here, but ended up wasting alot of time. Apparently his method supports changing validation rules at run-time.
This code shows merging a login and registration form in 1. There is more to it than whats posted here, but the idea here is to get dynamic input validation to work.