DotNetNuke (DNN) 2.x Module Architecture, Part I

In this article we go over the architecture of a DNN 2.x module, specifically the Survey module example included within the DotNetNuke distribution. In part one, we cover setting up a development project, and the user interface for our module.

If you're not familiar with DotNetNuke, be sure you visit http://www.dotnetnuke.com to learn more about this fast growing open source portal that you can use and develop against absolutely free.

DotNetNuke (DNN) has been out now for a little over a year and has really seen a tremendous amount of growth. The community is a very active and large community, which can easily be demonstrated by viewing the activity in the ASP.Net forums. In this article we will cover module creation for DotNetNuke, and specifically look at the Data Provider Model of DNN 2.x. We will not get into a step by procedural method of developing modules, but rather provide you with an overview of the architecture and starting point for developing your own custom modules for DNN.

What Are Modules?

Modules provide developers with the ability to extend the functionality of DotNetNuke. DotNetNuke provides a pluggable framework that can be expanded by the development of modules. A module container is provided by DotNetNuke to host a custom module. Modules can be developed in any .NET language, even though DNN is developed in VB.NET, a C# developer can still create a module that plugs into the core framework provided by DNN. This pluggable framework is accomplished by creating compiled private assemblies that expose and utilize interfaces specific to DNN. Once you compile the assembly, then just create a UI in the form of ascx files that allow your user to interact with your module.

Module Containers

Module containers provide several features for you as a developer. Besides being your way of interfacing with the DNN core framework, module containers also provide the following:

• Security mechanisms: You can define view and edit permissions for your modules. DNN will then handle the security checking for your module. You do not need to write your own security mechanism, rather use the role based security provided by the framework.
• Look and feel: Module containers can be customized with various looks, in addition the module container and DNN provide you with the ability to place the module within the DNN page. In addition, it also allows your users to customize the appearance of the module as well, for example minimize and maximize modes.
• Caching: As a performance mechanism you can define caching at the container level. This allows modules that do not need to be updated on every request to have their contents cached thus providing a performance improvement.

Configuring Your Development Environment

Now that we covered what modules actually are, lets go on and create a development project for our module. There are various methods for creating modules for DNN, but we prefer to configure a separate project for module creation and then compile the assemblies within the DNN bin folder. The following procedure  provides a method for configuring a portal module project in Visual Studio.NET.

1. Create a new class project, be sure to use a logical naming structure. For example: CompanyName.ModuleName.
2. When creating the new project folder, create a folder off of the DotNetNuke Root\DesktopModules\ directory.
3. Clear any namespace from the project properties. Right click on properties of the project, under general clear the root namespace box.
4. Add a reference to the DotNetNuke project in your new module project.

That's it for the base module assembly project. Now if you want to add a data provider assembly to your project you would follow the same procedure above except name your project CompanyName.ModuleName.SQLDataProvider (or Access depending on which database you're supporting). In addition to creating a reference to the DotNetNuke project, create a reference to your main module project and also the Microsoft.ApplicationBlocks.Data assembly. This is going to aid in the data abstraction.

Once you're project is done, it should look like the following in the solution explorer in Visual Studio.NET:

 

Figure 1.1 Solution Explorer View

Now let's first cover a little architecture for DNN. The following diagram is taken from the DotNetNuke documentation. This provides a look into how DNN is architected. First with the ascx controls which provide our user interface. The interface then communicates with the Business Logic Layer (BLL), as in the diagram this BLL is contained with the SurveyDB.vb class, and provides all data for our user interface. Below the BLL we have the Abstract Data Provider, we'll get more into this later, but this class provides an abstraction layer for our application. This provider is not database specific, rather our data provider class will provide methods that override the abstraction class and interaction with our specific database. The abstraction provider in this example is the DataProvider.vb class within the main survey module project. Below the abstraction layer we have our Data Access Layer, this class is specific to a vendor database and is unique based on what database we want our module to interact with. This class is the SQLDataProvider project as in the image above. Finally there is the Microsoft.ApplicationBlocks.Data which provides functions for our specific database interaction, and frees a developer from having to write specific SQL Server code.

  

Figure 1.2 DotNetNuke Architecture

Now that we covered project creation and architecture, let's get started writing some code. All code referenced in this article is the survey module example provided with DotNetNuke, so you can try it out for yourself.

Create Your Controls

First we need to create some controls for our user to interact with. In this example we have a Survey.ascx control, this control is the primary survey control that is public ally viewable for the user. The other controls are for managing the survey, these are the EditSurvey.ascx, and EditSurveyOptions.ascx controls.

 

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