NLayers Architecture

NLayers tries to provide a Layering solution to a typical ASP.NET application. This article is a continuation of the previous one about NLayers Introduction and Installation.

Intended Audience

This project framework is targeted for Architects or Developers with a good grip of ASP.NET and the Entity Framework.

Creating Solution

You can create a NLayers solution using the template as shown below. (You need to install the NLayers framework to see the following template.)

(For installation of NLayers please refer to the previous article.)

Projects in NLayers

After creating a new project from the NLayers ASP.NET Application template you can see the Solution Explorer as shown below:

Project	Description
NLayers.BusinessLogic	Business Logic part of the solution. Least expected to be changing the implementation classes throughout the lifetime of project.
NLayers.DataAccess.Interface	Decoupled design for Data Access.
NLayers.DataAccess.Implemenation	Implementation of Data Access Interface projet.
NLayers.Entity	Project containing the EDMX file of Entity Framework. It contains the entity classes.
NLayers.InstanceManager	Project providing instance management for Business Logic and Data Access classes.
NLayers.Web	ASP.NET Web Application. This project uses the WebApp class of InstanceManager to access Business Logic and Data Access instances.

Control Flow

The start up project should be NLayers.Web. The Web project will be using the Instance Manager project to invoke Business Logic and Data Access classes.
The entity project will be used by all the projects.

The following diagram depicts the control flow.

Layers in NLayers

The layers inside the NLayers Architecture are as the following:

Web Application representing the Presentation Layer
Business Logic representing the Business Logic Layer
Data Access representing the Data Access Layer

NLayers Advantages

The following are the advantages of NLayers over a typical monolithic application:

Decoupled Design / Separation of Concerns
Easier Manageability
Better support for Unit Testing
Easier Replace of Data Access Implementation
Instance Management
CRUD wrappers over Entity Framework
VS 2010 Project and Item Templates for Quick Start
Better support for Dependency Injection / Policy Injection

Source

This article is meant to provide information on NLayers project. You can access the latest source or documentation from:

http://nlayers.codeplex.com/

Summary

This article explained the Architectural part of the NLayers framework. In the next article you will see examples of how to use NLayers.