int InsertString( int nIndex, const char FAR* lpItem );
nIndex
Specifies the zero-based index of the position to insert the string. If this parameter is -1, the string is added to the end of the list.
lpItem
Points to the null-terminated string that is to be inserted.
Inserts a string into the list box. Unlike the AddString member function, InsertString does not cause a list with the LBS_SORT style to be sorted.
The zero-based index of the position at which the string was inserted. The return value is LB_ERR if an error occurs; the return value is LB_ERRSPACE if insufficient space is available to store the new string.
CListBox::AddString, LB_INSERTSTRING