Adds a string to a list box
[C++]
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.
Header: xldialog.h