An application sends an LB_GETSELITEMS message to fill a buffer with an array of integers that specify the item numbers of selected items in a multiple-selection list box.
LB_GETSELITEMS
wParam = (WPARAM) cItems; // maximum number of items
lParam = (LPARAM) (LPINT) lpnItems; // address of buffer
Windows 95 and Windows 98: The wParam parameter is limited to 16-bit values. This means list boxes cannot contain more than 32,767 items. Although the number of items is restricted, the total size in bytes of the items in a list box is limited only by available memory.
The return value is the number of items placed in the buffer. If the list box is a single-selection list box, the return value is LB_ERR.
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.
List Boxes Overview, List Box Messages, LB_GETSELCOUNT