Appendix A. MVVM Frameworks

By Muhammad Shujaat Siddiqi

The XAML community has been blessed with extraordinary developers who are always willing to volunteer their time. There are a myriad of MVVM frameworks available and it is a tough decision which one to choose from. This is because it is such a core architectural decision that it is nearly impossible to change the underlying framework in later stages of development without extreme risks. Here, MVVM Light Toolkit is our personal favorite.

Name	Author	License
MVVM Light Toolkit	Laurent Bugnion	MIT
Prism	Microsoft Patterns and Practices Team	Microsoft Patterns and Practices License (Custom)
Calcium	Daniel Vaughan	BSD
Caliburn	Rob Eisenberg	MIT
Cinch	Sacha Barber	MS-PL
Catel	Geert Van Horrik	MS-PL

As a guideline, we should be looking at how any particular framework will help us in incorporating MVVM in our design without sacrificing other enterprise architecture design requirements. We should also look at how loosely coupled it is with its own features. If a framework supports all these features but it forces you to use a particular Dependency Injection mechanism then you would definitely have to think about it. This would also help us in picking and choosing different features from different frameworks. It would be easier if they allow such choices. The base feature set to look for is as follows:

• INotifyPropertyChanged Implmementation (for base view model)

• ICommand Implementation

• Messenger (Mediator)

• Dialog support

• Validation (for base view model)

• Supported platforms (WPF, SL, WP, WinRT)

• Project templates and quick starts

• Documentation and active online community

In addition to the preceding features , these frameworks have also been incorporating other features (for example, logging) in order to be a complete enterprise application framework. You can also use those features when comparing these frameworks but since they are not particularly related to MVVM, we haven't discussed them here.