How to deal with cross-thread access exceptions?

Question

A common exception one can get when working with multiple threads in WPF is:

The calling thread cannot access this object because a different thread o

Answer 1

That would be several hundred lines of code, for something I "figured out".

But the summary is:

App_OnStartup generate a background thread

in the callback,

Call

Application.Current.MainWindow.Dispatcher.CheckAccess() - gets the exception Application.Current.Dispatcher.CheckAccess() does not