Introduction to NLayers

Introduction

In this article I would like to introduce a layering framework named NLayers. This article is intended for experienced developers or architects with a good understanding of ASP.NET and the ADO.NET Entity Framework.

The framework can also be downloaded from CodePlex: http://nlayers.codeplex.com/.

What is NLayers?

NLayers has the following:

1. Visual Studio 2010 solution template for layered applications
2. Contains Data Access wrapper class for CRUD operations

Following is the snapshot of a solution created using the NLayers template:

The core methods inside the DataAccess base class include the following:

• Insert()
• Update()
• Delete()
• GetAll()
• Where()

The layered application framework can be used to create the following types of projects:

• ASP.NET Web Application
• WCF Service Application
• Windows/WPF Application

Installation

Please download the latest setup file from the URL: http://nlayers.codeplex.com/

Use the Download button on the right side to get the NLayers.msi file.

Execute the MSI file, choose the installation folder, and click "Next" to complete the wizard. There will be a series of command lines executed for copying the templates and running the installation commands.

After the installation, open Visual Studio to view the NLayers installation.

Inside Visual Studio: Adding Solution

Inside Visual Studio, use File -> New Project to get the dialog box. You can see the NLayers ASP.NETApplication template from the NLayers group as shown below.

On creating the project template, we will see the Solution Explorer as given below.

Please make NLayers1.Web as the startup project if it is not.

Inside Visual Studio: Adding Items

For adding items, use the Add Item dialog from the respective project.

For example

NLayers Business Logic class should be added to the NLayers.BusinessLogic project. NLayers Data Access class should be added to the NLayers.DataAccess.Implementation project. NLayers Data Access Interface should be added to the NLayers.DataAccess.Interface project.

Documentation

Apart from this article, you can get the official documentation of NLayers from: http://nlayers.codeplex.com/documentation.

Using NLayers

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

Projects in NLayers

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

Control Flow

The startup project should be NLayers.Web. The web project will use the Instance Manager project to invoke Business Logic and Data Access classes. The entity project will be used by all projects. The following diagram depicts the control flow:

Layers in NLayers

The layers inside the NLayers architecture are as follows:

1. Web Application representing the Presentation Layer
2. Business Logic representing the Business Logic Layer
3. Data Access representing the Data Access Layer

NLayers Advantages

Following are the advantages of NLayers over a typical monolithic application:

• Decoupled design  / Separation of concerns
• Easier manageability
• Better support for Unit Testing
• Easier replacement 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 the NLayers project. You can access the latest source or documentation from: http://nlayers.codeplex.com/documentation.

Summary

This article explains the installation and usage of the NLayers framework.