CBN_DROPDOWN  JE_C41 

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