An application sends an LB_RESETCONTENT to remove all items from a list box.
LB_RESETCONTENT
wParam = 0; // not used; must be zero
lParam = 0; // not used; must be zero
This message has no parameters.
This message does not return a value.
If you create the list box with an owner-drawn style but without the LBS_HASSTRINGS style, the owner of the list box receives a WM_DELETEITEM message for each item in the list box.
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, WM_DELETEITEM