String Format for DateTime [C#]

时间：2023-03-08 18:36:21

This example shows how to format DateTime using String.Format method. All formatting can be done also using DateTime.ToString method.

Custom DateTime Formatting

There are following custom format specifiers y (year), M (month), d (day), h (hour 12), H (hour 24),m (minute), s (second), f (second fraction), F (second fraction, trailing zeroes are trimmed), t (P.M or A.M) and z (time zone).

Following examples demonstrate how are the format specifiers rewritten to the output.

[C#]

// create date time 2008-03-09 16:05:07.123

DateTime dt = new DateTime(2008, 3, 9, 16, 5, 7, 123);

String.Format("{0:y yy yyy yyyy}", dt);  // "8 08 008 2008"   year

String.Format("{0:M MM MMM MMMM}", dt);  // "3 03 Mar March"  month

String.Format("{0:d dd ddd dddd}", dt);  // "9 09 Sun Sunday" day

String.Format("{0:h hh H HH}",     dt);  // "4 04 16 16"      hour 12/24

String.Format("{0:m mm}",          dt);  // "5 05"            minute

String.Format("{0:s ss}",          dt);  // "7 07"            second

String.Format("{0:f ff fff ffff}", dt);  // "1 12 123 1230"   sec.fraction

String.Format("{0:F FF FFF FFFF}", dt);  // "1 12 123 123"    without zeroes

String.Format("{0:t tt}",          dt);  // "P PM"            A.M. or P.M.

String.Format("{0:z zz zzz}",      dt);  // "-6 -06 -06:00"   time zone

You can use also date separator / (slash) and time sepatator : (colon). These characters will be rewritten to characters defined in the current DateTimeForma­tInfo.DateSepa­rator andDateTimeForma­tInfo.TimeSepa­rator.

[C#]
// date separator in german culture is "." (so "/" changes to ".")

String.Format("{0:d/M/yyyy HH:mm:ss}", dt); // "9/3/2008 16:05:07" - english (en-US)

String.Format("{0:d/M/yyyy HH:mm:ss}", dt); // "9.3.2008 16:05:07" - german (de-DE)

Here are some examples of custom date and time formatting:

[C#]
// month/day numbers without/with leading zeroes

String.Format("{0:M/d/yyyy}", dt);            // "3/9/2008"

String.Format("{0:MM/dd/yyyy}", dt);          // "03/09/2008"

// day/month names

String.Format("{0:ddd, MMM d, yyyy}", dt);    // "Sun, Mar 9, 2008"

String.Format("{0:dddd, MMMM d, yyyy}", dt);  // "Sunday, March 9, 2008"

// two/four digit year

String.Format("{0:MM/dd/yy}", dt);            // "03/09/08"

String.Format("{0:MM/dd/yyyy}", dt);          // "03/09/2008"

Standard DateTime Formatting

In DateTimeForma­tInfo there are defined standard patterns for the current culture. For example property ShortTimePattern is string that contains value h:mm tt for en-US culture and value HH:mmfor de-DE culture.

Following table shows patterns defined in DateTimeForma­tInfo and their values for en-US culture. First column contains format specifiers for the String.Format method.

Specifier DateTimeFormatInfo property Pattern value (for en-US culture)
t ShortTimePattern h:mm tt
d ShortDatePattern M/d/yyyy
T LongTimePattern h:mm:ss tt
D LongDatePattern dddd, MMMM dd, yyyy
f (combination of D and t) dddd, MMMM dd, yyyy h:mm tt
F FullDateTimePattern dddd, MMMM dd, yyyy h:mm:ss tt
g (combination of d and t) M/d/yyyy h:mm tt
G (combination of d and T) M/d/yyyy h:mm:ss tt
m, M MonthDayPattern MMMM dd
y, Y YearMonthPattern MMMM, yyyy
r, R RFC1123Pattern ddd, dd MMM yyyy HH':'mm':'ss 'GMT' (*)
s SortableDateTi­mePattern yyyy'-'MM'-'dd'T'HH':'mm':'ss (*)
u UniversalSorta­bleDateTimePat­tern yyyy'-'MM'-'dd HH':'mm':'ss'Z' (*)
    (*) = culture independent

Following examples show usage of standard format specifiers in String.Format method and the resulting output.

[C#]
String.Format("{0:t}", dt);  // "4:05 PM"                         ShortTime

String.Format("{0:d}", dt);  // "3/9/2008"                        ShortDate

String.Format("{0:T}", dt);  // "4:05:07 PM"                      LongTime

String.Format("{0:D}", dt);  // "Sunday, March 09, 2008"          LongDate

String.Format("{0:f}", dt);  // "Sunday, March 09, 2008 4:05 PM"  LongDate+ShortTime

String.Format("{0:F}", dt);  // "Sunday, March 09, 2008 4:05:07 PM" FullDateTime

String.Format("{0:g}", dt);  // "3/9/2008 4:05 PM"                ShortDate+ShortTime

String.Format("{0:G}", dt);  // "3/9/2008 4:05:07 PM"             ShortDate+LongTime

String.Format("{0:m}", dt);  // "March 09"                        MonthDay

String.Format("{0:y}", dt);  // "March, 2008"                     YearMonth

String.Format("{0:r}", dt);  // "Sun, 09 Mar 2008 16:05:07 GMT"   RFC1123

String.Format("{0:s}", dt);  // "2008-03-09T16:05:07"             SortableDateTime

String.Format("{0:u}", dt);  // "2008-03-09 16:05:07Z"            UniversalSortableDateTime

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