Is it possible and necessary to support obsoleting axaml element?

[rabbitism]

We are currently many axaml resources in our theme library. But we barely find anyway to mark a resource as obsoleted in axaml, and provide a warning for downstream consumers. It is possible to support such a feature? Am i the only one need this feature?

[stevemonaco]

I've thought about the long-term stability of this before as well. While adding a new x:KeyObsolete directive could work for keyed resources (and promote IDE / compile-time checking), there are other things that can become obsolete or modified, such as pseudoclasses and even the ControlTemplate hierarchy (necessary so selectors stay valid). Maybe adding versioning to ControlTheme could be an alternative.

There's also a possibility to move obsolete resources into a separate, custom IResourceDictionary. You could then log warnings to debug at runtime when one of its keyed resources are fetched...but the dev still needs to load the resource to get the warning.

[maxkatz6]

XAML compiler itself has and emits [Obsolete] attribute warnings. But only when you reference any .NET member with such attribute. So, if your resources are shipped with x:Class, that's one way of doing it.

Marking whole XAML file as obsolete via an xml directory could be an idea too.