Following are the messages used with combo boxes.
CB_ADDSTRING
CB_DELETESTRING
CB_DIR
CB_FINDSTRING
CB_FINDSTRINGEXACT
CB_GETCOUNT
CB_GETCURSEL
CB_GETDROPPEDCONTROLRECT
CB_GETDROPPEDSTATE
CB_GETDROPPEDWIDTH
CB_GETEDITSEL
CB_GETEXTENDEDUI
CB_GETHORIZONTALEXTENT
CB_GETITEMDATA
CB_GETITEMHEIGHT
CB_GETLBTEXT
CB_GETLBTEXTLEN
CB_GETLOCALE
CB_GETTOPINDEX
CB_INITSTORAGE
CB_INSERTSTRING
CB_LIMITTEXT
CB_RESETCONTENT
CB_SELECTSTRING
CB_SETCURSEL
CB_SETDROPPEDWIDTH
CB_SETEDITSEL
CB_SETEXTENDEDUI
CB_SETHORIZONTALEXTENT
CB_SETITEMDATA
CB_SETITEMHEIGHT
CB_SETLOCALE
CB_SETTOPINDEX
CB_SHOWDROPDOWN
CBN_CLOSEUP
CBN_DBLCLK
CBN_DROPDOWN
CBN_EDITCHANGE
CBN_EDITUPDATE
CBN_ERRSPACE
CBN_KILLFOCUS
CBN_SELCHANGE
CBN_SELENDCANCEL
CBN_SELENDOK
CBN_SETFOCUS
WM_COMPAREITEM
WM_DRAWITEM
WM_MEASUREITEM