I want to have a text control that only accepts numbers. (Just integer values like 45 or 366)
What is the best way to do this?
IntCtrl, Masked Edit Control, and NumCtrl are all designed to do just this, with different levels of control.  Checkout the wx demo under "More Windows/Controls" to see how they work.
(Or, if you're instead really looking forward to doing this directly with a raw TextCtrl, I think you'd want to catch EVT_CHAR events, test the characters, and call evt.Skip() if it was an allowed character.)
Is it possible to limit TextCtrl to accept numbers only in wxPython?