Force Combo-box drop down

by Stuart Morris

Suppose you have a combo-box widget (named combo-box-1) and you want to drop down its built-in selection-list on some event. The following source will do just that.

{windows.i}
&GLOBAL-DEFINE CB_SHOWDROPDOWN 335
 
DEFINE VARIABLE retval AS INTEGER NO-UNDO.
 
  RUN SendMessage{&A} IN hpApi (INPUT  COMBO-BOX-1:HWND,
                                       {&CB_SHOWDROPDOWN},
                                       1,   /* True */
                                       0,
                                OUTPUT retval
                                )
                                NO-ERROR /* Stop C Stack Errors */.