If you don't need the full set of API calls, you maybe better off creating a COM import stub class. See how Mike Ward who wrote Desk Drive did it.
http://mike-ward.net/2008/09/02/a-lean-method-for-invoking-com-in-c/
https://github.com/mike-ward/DeskDrive/blob/master/src/DeskDrive/Shell32.cs