How to architect an asp.net mvc application?

Question

I have read little bit about architecture and also patterns in order to follow the best practices. So this is the architecture we have and I wanted to know what you think of it and any proposed changes or improvements -

• Presentation Layer - Contains all the views,controllers and any helper classes that the view requires also it containes the reference to Model Layer and Business Layer.
• Business Layer - Contains all the business logic and validation and security helper classes that are being used by it. It contains a reference to DataAccess Layer and Model Layer.
• Data Access Layer - Contains the actual queries being made on the entity classes(CRUD) operations on the entity classes. It contains reference to Model Layer.
• Model Layer - Contains the entity framework model,DTOs,Enums.Does not really have a reference to any of the above layers.

What are your thoughts on the above architecture ? The problem is that I am getting confused by reading about like say the repository pattern, domain driven design and other design patterns. The architecture we have although not that strict still is relatively alright and it works well and I think and does not really muddle things but I maybe wrong. I would appreciate any help or suggestions here. I am really looking for some real big issues that I have missed ... Thanks!

Answer 1

It slightly depends on the underlying reasons as to why you want a particular architecture, but assuming a standard MVC application with a small amount of separation of concerns to allow for interoperability and testability then the structure you have outlined is exactly right.

If you go for this then you should enforce it strongly with no exceptions. Saying the Model layer "Does not really have a reference to any of the above" is a bit vague - it should not reference any of the higher levels.

Other aspects such as a repository pattern would be introduced as the way in which the data layer is implemented - it does not dictate the layers themselves.