[Connect Update 16 .NET] How do we update UI if Async or Background worker is not allowed?

I was reading a thread from a few years ago that talked about an issue I am having now, I have a WPF application that has a long running process iterating files, I would prefer to run this process as a Task in a background thread, either by using backgroundworker or async, but it appears that Microsation does not allow you to load a DGN file from non-application thread.

Is there a way to update the UI and keep it responsive during this process? In VBA there's DoEvents, it doesn't release the UI but it does allow it to be refreshed/repainted. Any options on this?