I am using ViewModels with asp.net MVC3. One of the thing I am curious about is, suppose I have an entity named Customers and it has Add, Edit, Delete screens. Assume that they all have different properties requirements.
For eg. Add may have address field but the edit screen may not have edit screen, delete may only use customer name more than anything else.
My question is, how do you create ViewModels for this? Do you go with the approach of shared ViewModels between add, edit and delete i.e a single viewmodel class that handles all for you or do you prefer to create viewmodels classes / page?
Advantage with shared viewmodel is it reduces development time and we can reuse classes. But big problem with this is that if you are using tool like Automapper you may expected results for different screens.
Disadvantage with one viewmodel/page is that it increases development time. Which way should I go?
My approach to view models is to use shared view models until the requirements (the data transported) to the view is different. That means I’m using a shared view model for example for CreateAddress and EditAddress in case all data transported to the view is the same. In case an additional field needs to be displayed in the view for example in the CreateAddress view I’m refactoring my view models and using different view models for CreateAddress and EditAddress.
For example for DeleteAddress I’d use a distinct view model from start because I know that the data displayed in the DeleteAddress view is almost never the same as in Create/EditAddress.
Another approach is to use dynamic view models, since view models should/must not implement business logic and act as DTOs between controller and view this approach has some benefits (No need to create logic free, throw away DTOs).