Format
= Year last 2 digits
yy  = Year last 2 digits
yyyy  = Year as 4 digits
= Month number no-leading 0
mm  = Month number as 2 digits
mmm  = Month using ShortDayNames (Jan)
mmmm  = Month using LongDayNames (January)
= Day number no-leading 0
dd  = Day number as 2 digits
ddd  = Day using ShortDayNames (Sun)
dddd  = Day using LongDayNames  (Sunday)
ddddd  = Day in ShortDateFormat
dddddd  = Day in LongDateFormat
 
= Use ShortDateFormat + LongTimeFormat
= Hour number no-leading 0
hh  = Hour number as 2 digits
n = Minute number no-leading 0
nn  = Minute number as 2 digits
= Second number no-leading 0
ss  = Second number as 2 digits
z = Milli-sec number no-leading 0s
zzz  = Milli-sec number as 3 digits
= Use ShortTimeFormat
tt  = Use LongTimeFormat
 
am/pm  = Use after h : gives 12 hours + am/pm
a/p  = Use after h : gives 12 hours + a/p
ampm  = As a/p but TimeAMString,TimePMString
= Substituted by DateSeparator value
: = Substituted by TimeSeparator value
Example:

        h:m:s.z = 1:2:3.4
   hh:mm:ss.zzz = 01:02:03.004
              t = 01:02
             tt = 01:02:03
              c = 09/02/2000 01:02:03
     dd/mm/yy hh:mm:ss = 09/02/49 01:02:03
                 mmm = Feb
                mmmm = February
                 ddd = Tue
                dddd = Tuesday
               ddddd = 09/02/2049
              dddddd = 09 February 2049
              hhampm = 01AM
                   t = 01:02
                  tt = 01:02:03
          dd/mm/yyyy = 09/02/2049
tt, dddd dd. mmmm yyyy = 01:02:03, Tuesday 24. February 2049