There is no a strict sense to be attributed to the term "clear" when it comes to a whole set of all controls. It makes no general sense because controls are not necessarily independent, at least one radio button in a group, as John correctly pointed out, should be checked, etc.
But in many cases, you really need some method of putting all the controls in some initial state. Normally, you call it before a form is shown. If you want to call it again, you can also call it in your "Reset" buttons. (This looks a bit strange though; the usual name for it is called "Defaults" or something like that.) In most cases this is not needed, but I presume you have some reasons to do it.
I just want to point out, that in any more or less complex application such function should be semantic
and specific to your application. Here is why: you usually need to separate your UI from a data layer
. In this case, you have some data model which populates
UI and is modified when a user edits anything (just modifies) using the UI. This way, you have a uniform throughout the application, semantic methods of population and data update. In this approach, the setting up of initial UI state is no different: you have an initial-state instance of data and your "reset" is the population of the UI from this initial instance of the data model.
If you follow this simple approach, you can avoid doing the same thing in different ways and thus avoid many mistakes. After all, always remember one of the most important principles: Don't Repeat Yourself (DRY), see http://en.wikipedia.org/wiki/Don%27t_repeat_yourself