Not for entire application or particular class.
CurrentUICulture and CurrentCulture are settable per thread as discussed here Is there a way of setting culture for a whole application? All current threads and new threads?. You can't change InvariantCulture
at all.
Sample code to change cultures for current thread:
CultureInfo ci = new CultureInfo(theCultureString);
Thread.CurrentThread.CurrentCulture = ci;
Thread.CurrentThread.CurrentUICulture = ci;
For class you can set/restore culture inside critical methods, but it would be significantly safe to use appropriate overrides for most formatting related methods that take culture as one of arguments:
(3.3).ToString(new CultureInfo("fr-FR"))