Mark complained that a common control for associating extensions is *well* overdue.
This is a recurring theme I see in the comments: People complaining that Windows lacks some critical feature that it in fact already has. (In the case, Windows had the feature for over two years at the time the question was asked. Maybe the SDK needs a ribbon? j/k)
Windows Vista added the
Default Programs UI
as a control panel program,
and it also has a programmable interface.
You can
use
IApplicationAssociationRegistration
to query and set default associations,
and you can use
IApplicationAssociationRegistrationUI
to invoke the control panel itself on a set of associations
associated with your program.