What are the differences between FormView and Dialog in MFC? and can anyone suggest when to use FormView and when to use Dialog?
A dialog application just shows a dialog (and whatever controls you put in the dialog, plus any other controls you pop up from it, etc.)
A FormView gives you a fairly normal application with a main menu and such -- but the view part can also hold controls.
You'd use a dialog if you just want a dialog, and a formview if you want (possibly multiple) views that can hold controls. Big difference is that making it a dialog changes the basic nature of the entire application, where a formview just changes one view -- you could (for example) also have other (non-form) views if you wanted.