feat: x:Shared

[workgroupengineering]

What does the pull request do?

What is the current behavior?

What is the updated/expected behavior with this PR?

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

Fixes #15518

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051129-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[maxkatz6]

I will take a better look next week. @MrJul might be also interested in reviewing it.

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051143-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[MrJul]

The implementation can be simplified by removing duplicate code, reusing existing types, and having only the dictionary know whether an item is shared or not.

[MrJul]

Just a though for discussion:

While the feature is useful, needed, and matches WPF, Avalonia usually uses explicit factory types such as Template to represent non-shared contents.

Shouldn't we go the same way here, by specializing StaticResource to recognize template resources, instead of having x:Shared?

[BAndysc]

Shouldn't we go the same way here, by specializing StaticResource to recognize template resources, instead of having x:Shared?

My two cents as an user, while I agree Template is a good replacement, it would be very convenient to have x:Shared when porting WPF code.

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051171-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051173-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[MrJul]

Thank you for the changes, it's looking way better.
I've left a couple of comments for easily fixed issues. After that it should be good to go :)

[MrJul]

LGTM, thanks!

[avaloniaui-bot]

You can test this PR using the following package version. 11.2.999-cibuild0051295-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]