The CBN_EDITCHANGE notification message is sent after the user has taken an action that may have altered the text in the edit-control portion of a combo box. Unlike the CBN_EDITUPDATE notification message, this notification message is sent after Windows updates the screen. The parent window of the combo box receives this notification message through a WM_COMMAND message.
wParam
Specifies the identifier of the combo box.
lParam
Specifies the handle of the combo box in the low-order word, and specifies the CBN_EDITCHANGE notification message in the high-order word.
This message does not occur if the combo box has the CBS_DROPDOWNLIST style.