I use wxSmith to generate a new dialog with only a wxtextctrl and a button,the id of button is wxID_OK,so it can call validate automaticly,then i specfic a wxTextValidator with a wxFILTER_ALPHA and a pointer to wxString(_("123")) in wxTextcrtl's constructor.
when i show the dialog showmodal,the "123" does not appear at wxtextctrl,of course after i type some characters in it,the string i passed by pointer contains nothing,but the filter works,i can't type non-alphabeta in it.