Adds a string to a list box
int AddString( const char* pszItem );
Points to the null-terminated string that is to be added.
The zero-based index to the string in the list box. The return value is -1 if an error occurs.
Call this member function to add a string to a list box. The string is added to the end of the list.
Use InsertString to insert a string into a specific location within the list box.