Conditional validation groups in MVC3

I have an entity framework generated Model. When the model is initially created I only want to require a few properties, but afterwards I want to require a few more. Is there any notion of validation groups or conditional validation attributes th开发者_JAVA百科at would help me here?

I tried writing a custom conditional validation attribute that would just take another validation attribute in its parameter and just encapsulate other validation attributes but I get compiler errors saying "An attribute argument must be a constant express, typeof expression or array creation expression of an attribute parameter type"

Any idea how to accomplish this?

I have an entity framework generated Model

That's nice but not something that controllers should pass and take from views. In order to decouple the domain entities which, in theory, should be reusable among different applications from the way those entities are presented on a given view you could use view models. Those are classes which are specifically designed to the requirements of a given view. Thus you could have a CreateFooViewModel and UpdateFooViewModel both representing some domain model but of course with different validation rules (as validation rules differ between your views) and different formatting rules and properties selection. In order to ease the mapping between your view models and domain models you could use AutoMapper.