# File lib/tapkit/control/date_and_time.rb, line 198
                def to_s
                        s = sprintf("%04d-%02d-%02d %02d:%02d:%02d",
                                @year, @month, @day, @hour, @minute, @second) 

                        if @fraction.nil?
                                s
                        else
                                s + '.' + @fraction.to_s.split('.').last
                        end
                end