Using On key for undefined keys
From DataFlex Wiki
On_Key is a command used in Dataflex for trapping the action of keystrokes. All alphanumeric characters on the keyboard have actions define for them, but some keys such as /!@#$...etc do not.
You can define these special characters yourself. Generally this is done by working out the Hex value of the keystroke, and then defining the key with a Define_Symbol command.
Examples
Capturing the "/" symbol:
Define_Symbol Key_FwdSlash for |VI$802F On_Key Key_FwdSlash Send DoSomething