CBN_DROPDOWN

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 to combo box 
 

Remarks

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

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winuser.h.

See Also

Combo Boxes Overview, Combo Box Messages, CBN_CLOSEUP, WM_COMMAND