Question

I have four layer solution a medium size project:

1. Model (EF POCO entities)
2. Data (EF ObjectContext)
3. Services

4. asp net MVC question

   a)Should i have validation attributes- Dataanotation in Models or MVC project?

   b)where should i set ViewModel-s if in MVC then where do i fill ViewModels with data, in Controller? else if on other project should create Repository for VewModel?

   c) should ViewModel have validation>?

Answer 1

A, C) If you have view models that are different from your DTOs, then you might prefer to use DataAnnotations in both types. This way, you can validate before you try to persist and again as you persist in case your DTOs are used outside the scope of your MVC app.

B) I usually tuck my view models into the Models folder of my MVC app and my DTOs into a data project that is separate from my MVC app. I use AutoMapper a LOT to copy values between my view models and my DTOs.