N-Tier Architecture - Structure with multiple projects in VB.NET
- by focus.nz
I would like some advice on the best approach to use in the following situation...
I will have a Windows Application and a Web Application (presentation layers), these will both access a common business layer. The business layer will look at a configuration file to find the name of the dll (data layer) which it will create a reference to at runtime (is this the best approach?).
The reason for creating the reference at runtime to the data access layer is because the application will interface with a different 3rd party accounting system depending on what the client is using. So I would have a separate data access layer to support each accounting system. These could be separate setup projects, each client would use one or the other, they wouldn't need to switch between the two.
Projects:
MyCompany.Common.dll - Contains interfaces, all other projects have a reference to this one.
MyCompany.Windows.dll - Windows Forms Project, references MyCompany.Business.dll
MyCompany.Web.dll - Website project, references MyCompany.Business.dll
MyCompany.Busniess.dll - Business Layer, references MyCompany.Data.* (at runtime)
MyCompany.Data.AccountingSys1.dll - Data layer for accounting system 1
MyCompany.Data.AccountingSys2.dll - Data layer for accounting system 2
The project MyCompany.Common.dll would contain all the interfaces, each other project would have a reference to this one.
Public Interface ICompany
ReadOnly Property Id() as Integer
Property Name() as String
Sub Save()
End Interface
Public Interface ICompanyFactory
Function CreateCompany() as ICompany
End Interface
The project MyCompany.Data.AccountingSys1.dll and MyCompany.Data.AccountingSys2.dll would contain the classes like the following:
Public Class Company
Implements ICompany
Protected _id As Integer
Protected _name As String
Public ReadOnly Property Id As Integer Implements MyCompany.Common.ICompany.Id
Get
Return _id
End Get
End Property
Public Property Name As String Implements MyCompany.Common.ICompany.Name
Get
Return _name
End Get
Set(ByVal value as String)
_name = value
End Set
End Property
Public Sub Save() Implements MyCompany.Common.ICompany.Save
Throw New NotImplementedException()
End Sub
End Class
Public Class CompanyFactory
Implements ICompanyFactory
Public Function CreateCompany() As ICompany Implements MyCompany.Common.ICompanyFactory.CreateCompany
Return New Company()
End Function
End Class
The project MyCompany.Business.dll would provide the business rules and retrieve data form the data layer:
Public Class Companies
Public Shared Function CreateCompany() As ICompany
Dim factory as New MyCompany.Data.CompanyFactory
Return factory.CreateCompany()
End Function
End Class
Any opinions/suggestions would be greatly appreciated.
