How is SqlStringLocalizer turned into IStringLocalizer<SharedResource>?

[veimis]

The SqlStringLocalizerFactory.Create -method creates a new SqlStringLocalizer, which derives from IStringLocalizer.

The AboutController however expects a IStringLocalizer<SharedResource> and that is injected by the DI container, but how is the SqlStringLocalizer cast into IStringLocalizer<SharedResource> (as it does not derive from IStringLocalizer<T>)?

Suppose I'd like to create the SqlStringLocalizer manually (without the DI), would it be possible?
(And cast it to IStringLocalizer<SharedResource> so I can pass it along)

Thanks in advance,
Ilkka