Project Naming Convention Feedback Please

I am creating a ASP.NET MVC 3 application using Entity Framework 4. I am using the Repository/Service Pattern and was looking for feedback.

I currently have the following:

MVC Application (GTG.dll)

• GTG
• GTG.Controllers
• GTG.ViewModels

Business POCO's (GTG.Business.dll)

• This contains all business objects (Customer, Order, Invoice, etc...)

EF Model/Repositories (GTG.Data.dll)

• GTG.Business (GTG.Context.tt) I used the Entity POCO Generator Templates.
• GTG.Data.Repositories

Service Layer (GTG.Data.Services.dll)

• GTG.Data.Services - Contains all of the service objects, one per aggregate root.

The following is a little sample code:

Controller

Namespace Controllers
    Public Class HomeController
        Inherits System.Web.Mvc.Controller

        Function Index() As ActionResult
            Return View(New Models.HomeViewModel)
        End Function

    End Class
End Namespace

Model

Namespace Models
    Public Class HomeViewModel

        Private _Service As CustomerService
        Public Property Customers As List(Of Customer)

        Public Sub New()
            _Service = New CustomerService
            _Customers = _Service.GetCustomersByBusinessName("Striano")

        End Sub

    End Class
End Namespace

Service

Public Class CustomerService
    Private _Repository As ICustomerRepository

    Public Sub New()
        _Repository = New CustomerRepository

    End Sub

    Function GetCustomerByID(ByVal ID As Integer) As Customer
        Return _Repository.GetByID(ID)
    End Function

    Function GetCustomersByBusinessName(ByVal Name As String) As List(Of Customer)
        Return _Repository.Query(Function(x) x.CompanyName.StartsWith(Name)).ToList

    End Function

End Class

Repository

Namespace Data.Repositories
    Public Class CustomerRepository
        Implements ICustomerRepository

        Public Sub Add(ByVal Entity As Business.Customer) Implements IRepository(Of Business.Customer).Add

        End Sub

        Public Sub Delete(ByVal Entity As Business.Customer) Implements IRepository(Of Business.Customer).Delete

        End Sub

        Public Function GetByID(ByVal ID As Integer) As Business.Customer Implements IRepository(Of Business.Customer).GetByID
            Using db开发者_StackOverflow社区 As New GTGContainer
                Return db.Customers.FirstOrDefault(Function(x) x.ID = ID)
            End Using
        End Function

        Public Function Query(ByVal Predicate As System.Linq.Expressions.Expression(Of System.Func(Of Business.Customer, Boolean))) As System.Linq.IQueryable(Of Business.Customer) Implements IRepository(Of Business.Customer).Query
            Using db As New GTGContainer
                Return db.Customers.Where(Predicate)
            End Using
        End Function

        Public Sub Save(ByVal Entity As Business.Customer) Implements IRepository(Of Business.Customer).Save

        End Sub
    End Class
End Namespace

The separation of your project is very good and contains exactly the layers it should. The problem is that you have a strong coupling between your layers making your code impossible to unit test.

Examples:

Your view model is strongly coupled to a specific implementation of the service:

_Service = New CustomerService

Your service is strongly coupled to a specific implementation of the repository:

_Repository = New CustomerRepository

To improve this code and weaken the coupling you should consider using constructor injection and a DI framework.

So for example have your service constructor would take a ICustomerRepository argument and assign the private field to it instead of hardcoding a new instance manually. Also have your service implement an interface and do the same constructor injection in your HomeController constructor so that it has access to the service.