An application sends an LB_ADDSTRING message to add a string to a list box. If the list box does not have the LBS_SORT style, the string is added to the end of the list. Otherwise, the string is inserted into the list and the list is sorted.
LB_ADDSTRING
wParam = 0; // not used; must be zero
lParam = (LPARAM) (LPCTSTR) lpsz; // address of string to add
Parameters
lpsz
Value of lParam. Points to the null-terminated string that is to be added.
If you create the list box with an owner-drawn style but without the LBS_HASSTRINGS style, the value of the lpsz parameter is stored as item data instead of the string it would otherwise point to. You can send the LB_GETITEMDATA and LB_SETITEMDATA messages to retrieve or modify the item data.
Return Values
The return value is the zero-based index of the string in the list box. If an error occurs, the return value is LB_ERR. If there is insufficient space to store the new string, the return value is LB_ERRSPACE.
Remarks
If you create an owner-drawn list box with the LBS_SORT style but not the LBS_HASSTRINGS style, the system sends the WM_COMPAREITEM message one or more times to the owner of the list box to place the new item properly in the list box.
See Also
LB_DELETESTRING, LB_INSERTSTRING, LB_SELECTSTRING, WM_COMPAREITEM