Architecting Silverlight LOB applications

This post is an introduction to a series of posts that I will be doing about how we can architect an enterprise data-centric Silverlight application. While Silverlight is a powerful platform to create great interactive user experiences for Web, Desktop (and now) Mobile, it is also Microsoft’s best bet to create a multi-platform, cross-browser technology.

A lot of people think of Silverlight as just another Adobe Flash rival because of the RIA aspects both technologies offer and the strong multimedia support that Silverlight has. While this is true, we can get much more from Silverlight if we think of it as good technology for the software industry in Information Technologies. IT projects are all about manipulation, visualization and understanding data.

Silverlight, which is a subset of WPF (excellent to deal with data through data binding) and still a .NET application, when combined with today’s most popular patterns and some key technologies for software engineering, can be a very productive, straight-forward, reliable and successful technology to build this kind of applications, and at the same time, provide great UX.

In this series of posts I will try to cover key aspects when you are architecting an application that can start small, are meant to last for years and over time evolve into a bigger application due to new requirements and be developed by multiple teams without resulting in a big mess of code that no one ever wants to touch.

Such applications often are built using the following principles:

  • Separation of Concerns
    • The most important principle. Ability to divide and conquer by creating layers in your application that are meant to deal with a specific problem, task or functionality, thus reducing complexity. The rest of the principles are all based on this one.
  • Loosely coupling
    • Ability to create multiple components that can work together but do not depend on each other.
  • Flexibility
    • Ability to respond to future changes, either by completely switching the underlying technology or business needs.
  • Extensibility
    • Ability to create new functionality by extending or reusing existing one.
  • Modularity
    • Ability to create well defined (cohesion) independent business areas in your application that can be evolved separately, integrate with each other and even be deployed separately.
  • Testability
    • Ability to avoid/prevent unexpected bugs by changes or new functionality you make, by testing your application’s logic, behavior or dependencies.
  • Maintainable
    • Ability to quickly find the code you need to change, understand it and change it, even if the one who wrote it in the first place is not around anymore (happens frequently).
  • Reutilization
    • Ability to reduce code by creating components that will be reused by other components that require a specific functionality.
  • UI Independence
    • Ability to switch your presentation controls without breaking neither your presentation logic nor your application logic.
  • Localization
    • Ability to target multiple languages, thus increasing your range of customers.

I’m thinking in starting with an overall architecture, choose the right technologies, build a small application on top of it and then keep composing it. I’ll start with .NET 3.5 and later on move to .NET 4.

See you soon!


Silverlight for Windows Phone 7 and Symbian sooner than we think?

While MIX10 is taking place, it is expected that Microsoft anounces a Silverlight beta release along with developer tools for Symbian (running on Nokia S60 5th Edition platform, source) and also for Windows Phone 7 series.

I’ve been developing web app’s since I’ve started my career but I had the chance to develop some mobile app’s as well, and I gotta tell you, for me developing for mobile devices is very challenging and much more interesting than web app’s. 

I really enjoy .NET Compact Framework but when you want to do some cool UX stuff it’s a pain in the butt.

Last couple of years I’ve been working mostly with Silverlight/WPF and I’ve been waiting for a Silverlight release for Windows Mobile 7 (now called Windows Phone 7 series) for a long time.

I can’t wait until I start developing for mobile devices with Silverlight, and now being able to target Symbian devices as well it feels like the cherry on top of the cake.

On a side note, I’ll be attending Microsoft’s technology event in Portugal, Techdays 2010 on 20th,21st,22nd of April, and I’ll be most interested on Architecture, Web/UX, Mobility and Cloud sessions. I hope everyone has a chance to participate!

Source-code used in this blog is now available

Hi everyone,

I’ve just created a project at google.code to host the source-code of examples in this blog.

Check it out at

I use Tortoise to access the SVN repository.

As I keep posting I will be updating the sources at google.code.

If anyone has trouble accessing it I will be willing to help.

Update: I’m not using SVN at anymore. From now on I will be hosting projects on and code samples on