WPF (and future MAUI): framework support

[vvdb-architecture]

This is more a discussion topic than a real issue.

Today, we are using PRISM for UWP/WPF/Xamarin Forms.
There is a PRISM for MAUI but it's not usable in WPF.

We should evaluate and investigate which class library (if any) we will use for WPF/MAUI applications moving forward.

PRISM is a very complex library, implementing the stuff we want and a lot of other stuff we don't use. It is also based on a dependency injection principle which in its current form doesn't play well with Microsoft's DI for two reasons:

• the DI container abstraction cannot be immutable
• the DI container requires the registration and resolution by name.

The author of PRISM is very opinionated and see this as non-negotiables (see PrismLibrary/Prism#1352), even though immutability is only user for modules (see PrismLibrary/Prism#1579).

For this reason only, Arc4u needs composition container of MEF2, which brings another set of unnecessary features. There is a way to use PRISM in .NET Core (5.0+) without any MEF, see the POC and related assemblies, but it remains an uneasy marriage of convenience.

We should investigate if we can't use a smaller, leaner framework supporting MVVM, and which is platform agnostic.
For example, the MVVM Toolkit

[GFlisch]

Personally, I am also in favor of MVVM Toolkit. The community is doing a great job.

The persons behind Prism have also admitted this and the toolkit is answering all the needs we have to build a UI. It is also less dangerous regarding the dependency. Prism is built by 2 persons (having some concerns about the fact that they don't win money based on their product).

Toolkit integrates messaging and support also Wpf. I don't invest time for the moment to switch from Prism to Toolkit in Wpf. I want and see more stability on MAUI before taking any decision.