CBN_DROPDOWN Overview  Group

The CBN_DROPDOWN notification message is sent when the list box of a combo box is about to be made visible. The parent window of the combo box receives this notification message through the WM_COMMAND message.

CBN_DROPDOWN 

idComboBox = (int) LOWORD(wParam);  // identifier of combo box 

hwndComboBox = (HWND) lParam;       // handle of combo box 

 

Remarks

This notification message can occur only for a combo box with the CBS_DROPDOWN or CBS_DROPDOWNLIST style.

See Also

CBN_CLOSEUP, WM_COMMAND