NSK is a reference implementation of a .NET layered application. Entirely written in C#, NSK can serve as a sort of blueprint for your architecture. In NSK, you find an MVP presentation layer and a service layer implemented as vanilla .NET classes. You’ll also find a domain model and a handmade data access layer, plus test projects. The data model is the popular Northwind database.

Let’s briefly have a look at the projects and the architectural characteristics of the layers. Figure A-1 shows the solution window in Visual Studio 2008.

The solution is articulated in two main sections: source code and tests. The source code area is divided into sections for the data access layer, business layer, and presentation layer. The test area is divided into two distinct testing environments: MSTest incorporated in Visual Studio 2008 and NUnit. (See http://www.nunit.org.)