LBN_SELCHANGE
The LBN_SELCHANGE notification message is sent when the selection in a list box is about to change. The parent window of the list box receives this notification message through a WM_COMMAND message.
wParam
Specifies the identifier of the list box.
lParam
Specifies the handle of the list box in the low-order word, and specifies the LBN_SELCHANGE notification message in the high-order word.
This notification is not sent if the selection is changed by the LB_SETCURSEL message.
This notification applies only to a list box that has the LBS_NOTIFY style.
The LBN_SELCHANGE notification is sent for a multiple-selection list box whenever the user presses an arrow key, even if the selection does not change.