Note that custom date and time formats may not produce the result you want when you program runs in different locales. For example, the date January 23, 2010 should be displayed as 1/23/2010 in the United States but in as 23/1/2010 in England. If your code uses custom date and time formats, users may see a format they don't expect. To avoid this sort of problem, use the standard date and time formats whenever possible.

You can use numeric formatting characters to display date and time values in particular formats. These formats work with a variable's ToString method as well as with String.Format. For example, the code DateTime.Now.ToString("M/dd/yyyy") returns the current date in the format 1/23/2010.

This example builds a ListView that demonstrates the various custom date and time formats. It then uses code from the example Make a program generate HTML table code for ListView data and display it in a WebBrowser control in C# to convert the results into the following HTML table.

Date Formats
Name	Format	Result
Day of month (1 - 31)	d	15
Day of month (01 - 31)	dd	15
Abbreviated day of week	ddd	Mon
Full day of week	dddd	Mon
Month (1 - 12)	M	3
Month (01 - 12)	MM	03
Month abbreviation	MMM	Mar
Month name	MMMM	March
Year (0 - 99)	y	10
Year (01 - 99)	yy	10
Year (minimum 3 digits)	yyy	2010
Year (4 digits)	yyyy	2010
Year (5 digits)	yyyyy	02010
Era	g	A.D.
Era	gg	A.D.
Date separator	/	/
Time Formats
Name	Format	Result
Hour (1 - 12)	h	6
Hour (01 - 12)	hh	06
Hour (1 - 23)	H	18
Hour (01 - 23)	HH	18
Minute (0 - 59)	m	37
Minute (00 - 59)	mm	37
Second (0 - 59)	s	12
Second (00 - 59)	ss	12
Tenths of seconds	f	1
Hundredths of seconds	ff	15
Milliseconds	fff	157
Ten thousandths of seconds	ffff	1570
Hundred thousandths of seconds	fffff	15700
Millionths of seconds	ffffff	157000
Ten millionths of seconds	fffffff	1570000
A/P	t	P
AM/PM	tt	PM
If non-zero, tenths of seconds	F	1
If non-zero, hundredths of seconds	FF	15
If non-zero, milliseconds	FFF	157
If non-zero, ten thousandths of seconds	FFFF	157
If non-zero, hundred thousandths of seconds	FFFFF	157
If non-zero, millionths of seconds	FFFFFF	157
If non-zero, ten millionths of seconds	FFFFFFF	157
UTC hour offset	z	-6
UTC hour offset with leading 0	zz	-06
UTC hour and minute offset	zzz	-06:00
Time separator	:	:

Note that some of the formats only work properly when embedded in a longer format string. For example, "M" by itself returns a month plus year format as in "March 15" (on my system). If you add a % before the character (as in "%M), then the character works properly.

See also:

• Use the DateTime class's standard formatting methods in C#
• Use custom date and time formats in C#
• Use custom numeric formats in C#
• Use standard date and time formats in C#
• Use standard numeric formats in C#
• Use standard numeric formats in C# (earlier version)