winrt application framework - windows-runtime

Question

What is the better framework for development Windows Store application?
I have used http://metroprism.codeplex.com/ but now I want to use Caliburn.Micro or MVVM light for another project.
I have looked through several application examples for these frameworks but they were not complicated enough for me to estimate usage in bigger projects.
These two ones are completely documented but the problem I think is that documentation for winrt mixed with WP7, Silverlight and WPF and I doubt a bit in supporting all features and practices of using exactly for Windows Store application.
Could you give me advice what is the better one? Or what are the good practices in development for Winrt with modularity supporting like in Prism for WPF and Silverlight.
Thanks.

Answer 1

MVVM Light and Caliburn.Micro basically do the same thing but they do it using opposing "philosophies of development" in MVVM.
MVVM Light is a "view first" approach. In this approach the ViewModel is instantiated in by the View. In MVVM Light this is done via something called the ViewModelLocator, a static class that binds a public property directly to the DataContext of the View.
Caliburn.Micro is a "viewmodel first" approach. Here you find that the viewmodel and view are created by an IOC mechanism that binds the two together. You navigate from viewmodel to viewmodel, with the views being generated in response to the navigation to a ViewModel.
They both have different features:
MVVM Light has a really nice messaging system for allowing view models to communicate with each other in a loosely-coupled way.
MVVM Light has a really simple mechanism for injecting design-time data into your views. Basically it swaps out your runtime services with design-time services that feed data to your viewmodels and, in turn your view. This makes design time data really easy to use.
Caliburn.Micro has an amazing data-binding setup, where it handles most of your databinding scaffolding for you. Basically, it maps the names of methods and properties to the names of controls in the view and autowires them. This saves lots of code and is a really, really nice feature.
Caliburn.Micro uses a "Convention over Configuration" mechanism to map views to viewmodels. MainView maps to MainViewModel, etc. This means you've got no configuration, you just need to make sure that you've got your naming conventions sorted out.
I've used both frameworks (Caliburn.Micro for WP7 and MVVM Light for Windows 8 Store Apps) and like them both for different reasons. MVVM Light is easier to start using but Caliburn.Micro is probably more powerful. I've found them both more than adequate for writing moderately complex applications quickly.

Answer 2

Caliburn.Micro gives you clean XAML at the cost of some magic. MVVM Light is a clean and simple framework that is easy to understand and works well. Prism seems to be a bit heavier than MVVM Light and more business app oriented - it does more than just MVVM. There are many things to consider. Choosing what you already know will let you focus on adding features, but learning a new framework can certainly be a good learning experience helpful in future choices - so you could pick something you haven't used before if you want to learn. You could also write your own framework and only include what you need. I usually go somewhere between roll your own and MVVM Light because that is what I know, though if I were to build a bigger enterprise app - Prism might be better suited for the task. I haven't used Caliburn.Micro because the novelty of different MVVM approaches wore off for me and I just want to create apps. With WinRT a roll-your-own-framework approach is easier than with any platform before because the basic project templates already give you some foundations as I wrote in my Minimalistic MVVM blog post. I would recommend that approach if you already tried MVVM and want to use only the pieces you need - the framework will grow with your app. You can just grab pieces of code from other frameworks if you need them or write your own implementations of the patterns you need.
To summarize
If you want to learn - try something you haven't tried before or write your own framework
If you want to create an app quickly and it is not a huge app - use what you know or go minimalistic and don't use anything but what you get from the templates
If you are building a big app with lots of features - consider Prism or rather first think whether Windows Store is the right target platform for you since it seems to be focusing more on simple in and out tablet apps