[Skia] ApplicationData.Current.LocalFolder redirects to %appdata%

[jeromelaban]

Current behavior

ApplicationData.Current.LocalFolder redirects to %appdata%, but should redirect to a more app-specific folder.

Expected behavior

Writing to ApplicationData.Current.LocalFolder should be specific to the running app.

Anything else we need to know?

Note for contributors

The behavior for this is currently undefined, as it is mapped to the UWP behavior. We should be mapping to the behavior that ApplicationData.Current.LocalFolder shows when running a unpackaged WinAppSDK app for the same API.

[MartinZikmund]

This will be a breaking change, but should probably be done soon.

[MartinZikmund]

@jeromelaban I think this is one of the breaking changes that are really needed for the next major release

[MartinZikmund]

Currently unpackaged WinAppSDK apps just crash when ApplicationData.Current is used. See microsoft/WindowsAppSDK#2639, microsoft/WindowsAppSDK#2621 .

Because we have the Package.appxmanifest, I think for the default behavior we can read the publisher and app id from there, and also provide a FeatureConfiguration to let the developer to override the path and store the app data/settings somewhere else as needed, does that sound like a good solution @jeromelaban ?

[jeromelaban]

altering the path using publisher and appid makes sense yes, as for feature configuration, I wonder if an helper class would be more appropriate?