I have created my own conditional validation attribute to validate my MVC model on both the client and the server by inheriting from RequiredAttribute and imple
RequiredAttribute
I had a similar problem where I wanted to revalidate a datepicker field using jquery validate and jquery ui. This post helped me figure it out.
The key, is just add a callback to the valid method for that selector. Something like:
$(".requiredif").change(function() { $(this).valid(); })