MVVM Toolkit: ObservableValidator and ObservableRecipient together ?

[HispidaBytes]

Hi,

I am trying to migrate my application to MVVM Toolkit as MVVM framework and during the operation a question came up:
I wanted to know if it might be a good idea to have an "Observable" type that implements the same functionality as "ObservableRecipient" and "ObservableValidator".
I find myself in the situation where I have a ViewModel class that needs both messaging functionality between ViewModels and property validation.
Could this be a good idea or are there alternatives that I haven't considered?

Thank you 😊

[michael-hawker]

@HispidaBytes this can be done with the new source generator support added in 7.1. @Sergio0694 was there an example of this somewhere you had yet? I know you haven't really updated the docs yet as the source generator stuff is still being worked on and considered 'in preview'.

[bukowa]

Hey, it's been a while, any chance to get updated answer?

[echoix]

There's an [ObservableRecipient] attribute that can be used on classes that are based on ObservableObject (directly or indirectly), such as ObservableValidator. It will skip creating constructors if the same signature already exists. There is also a conflict with ObservableRecipient.SetProperty{T}(ref T, T, bool, string?) and ObservableValidator.SetProperty{T}(ref T, T, bool, string?), so the ObservableRecipient one(s) won't be created.

If you need to have your constructors, and also need the ones generated for ObservableRecipient, but are skipped (symptom: Messenger instance not initialized when leaving the constructor), create a class that is based on ObervableValidator, and has the [ObservableRecipient] attribute, and use that class as your base class for the class you want as ObservableRecipient and ObservableValidator. That way, you can keep a parameterless constructor for you own, and the two other parameterless constructors will still be called and used.

Pseudocode:

[ObservableRecipient]
public partial class ObservableRecipientValidator: ObservableValidator { }

// Your class
public partial class MyClass: ObservableRecipientValidator { }