1. An object oriented method for mode switching between build and run modes in a computer application builder program, comprising the steps of: providing a plurality of dictionaries as dam structures which use keys to identify objects which implement methods, wherein at least first and second ones of said dictionaries define one or more methods for a first and a second mode and a third one of said dictionaries is a mode dictionary which defines build and run modes for an application program being programmed using the computer application builder program; identifying one or more keys for each of said dictionaries; and switching between build and run modes of the application program being programmed using the computer application builder program by using said one or more keys for said mode dictionary to retrieve a method dictionary for a corresponding mode.