N-Tier Application Design

I am fairly new to Arhitecture Designs in OOP ( I'm coming from programming robotics, so it's a bit of a struggle ). The team that I am taking part of is creating a rather large application and the Leading Project Manager presented us with the requirements and in that requirements we must use Layers in creating the modules. The technologies we are using are C# WinForms and Oracle for the data-store.

My module consists of User Administration and I have tried to separate the logic from the implementation, so I have the following arhitecture:

• Business Layer


• Data Layer


• Presentation Layer

I am using the Repository Pattern and IoC with EF and everything looks and works fine but now my boss has told me that I need to seperate the Presentation Layer from the Data Layer completely. The problem consists that from the Presentation Layer I use IoC and if I want to create a User object for example I do the following:

_userRepo.InsertNewUser(new User { props here } ); . So this is incorrect because I access the DAL directly. My boss has told me that I need another layer that isolates these kind of calls and implement Business Rules ( ?! )

I have searched and researched the internet and I found nothing of help ( mainly because everything is filtered here at work ).

I think my boss wants something of a Domain Layer / Service Layer but I have no ideea how to implement it in the current design. I can post the project without any problem, any sensitive data will be removed from the code.

Any help would be appreciated.