public String QueryItinerary(Transaction context, Customer customer) { var buf = new StringBuilder(1024); buf.Append(Flights.QueryReserved(context, customer)); if (buf.Length > 0) { buf.Append(','); } buf.Append(Cars.QueryReserved(context, customer)); if (buf.Length > 0) { buf.Append(','); } buf.Append(Rooms.QueryReserved(context, customer)); return(buf.ToString()); }