It was good to see that an updated framework for Prism that works with WinRT available. We’ve used it now on a couple of Win8 app’s and it has worked reasonable well.
It’s focus is on rapid app delivery and it has useful features to cater for some Win8 specific concerns; such as assembling Flyouts and handling SessionState. These are useful features that save a modicum of time when starting a new App.
Its major flaw (in my opinion) is it lacks support for other .Net variants. I was hoping to see more abstractions being moved into a Portable Class library; that could allow for code re-use across classic .Net, Windows 8 Apps and Windows Phone App. Features can only be used within the realms of a Windows 8 app (with the exception of the EventAggregator.)
This also has a knock-on effect with unit testing.
Unit testing a Win 8 is severely limited. There are challenges with build integration and a lack of a decent mocking framework. A common technique is to architect the App in such a way that the UI logic (ViewModel’s) live in a separate PCL assembly. The logic can then be tested using classic .Net assemblies to take advantage of all the great Mocking frameworks available.
Unfortunately, the Prism downloaded from Codeplex targets .Net for WinRT and makes this technique impossible.
Its possible to modify the Prism framework to cater for this unit testing technique. I done so on a recent project and had good success…However its a shame it didn’t come out of the box this way.