C#格式化數值結果表(格式化字符串)(2)

The group separator is especially useful for formatting currency values which require that negative values be enclosed in parentheses. This currency formatting example at the bottom of this document makes it obvious:

Dates

Note that date formatting is especially dependant on the system's regional settings; the example strings here are from my local locale.

SpecifIEr Type Example (Passed system.DateTime.Now) d Short date 10/12/2002 D Long date December 10, 2002 t Short time 10:11 PM T Long time 10:11:29 PM f Full date & time December 10, 2002 10:11 PM F Full date & time (long) December 10, 2002 10:11:29 PM g Default date & time 10/12/2002 10:11 PM G Default date & time (long) 10/12/2002 10:11:29 PM M Month day pattern December 10 r RFC1123 date string Tue, 10 Dec 2002 22:11:29 GMT s Sortable date string 2002-12-10T22:11:29 u Universal sortable, local time 2002-12-10 22:13:50Z U Universal sortable, GMT December 11, 2002 3:13:50 AM Y Year month pattern December, 2002

The 'U' specifIEr seems broken; that string certainly isn't sortable.

Custom date formatting:

SpecifIEr Type Example Example Output dd Day {0:dd} 10 ddd Day name {0:ddd} Tue dddd Full day name {0:dddd} Tuesday f, ff, ... Second fractions {0:fff} 932 gg, ... Era {0:gg} A.D. hh 2 digit hour {0:hh} 10 HH 2 digit hour, 24hr format {0:HH} 22 mm Minute 00-59 {0:mm} 38 MM Month 01-12 {0:MM} 12 MMM Month abbreviation {0:MMM} Dec MMMM Full month name {0:MMMM} December ss Seconds 00-59 {0:ss} 46 tt AM or PM {0:tt} PM yy Year, 2 digits {0:yy} 02 yyyy Year {0:yyyy} 2002 zz Timezone offset, 2 digits {0:zz} -05 zzz Full timezone offset {0:zzz} -05:00 : Separator {0:hh:mm:ss} 10:43:20 / Separator {0:dd/MM/yyyy} 10/12/2002

Enumerations

SpecifIEr Type g Default (Flag names if available, otherwise decimal) f Flags always d Integer always x Eight digit hex.

Some Useful Examples

String.Format("{0:$#,##0.00;($#,##0.00);Zero}", value);

This will output "$1,240.00" if passed 1243.50. It will output the same format but in parentheses if the number is negative, and will output the string "Zero" if the number is zero.

String.Format("{0:(###) ###-####}", 18005551212);

This will output "(800) 555-1212".

變量.ToString()

字符型轉換 轉為字符串 12345.ToString("n"); //生成 12,345.00 12345.ToString("C"); //生成 ￥12,345.00 12345.ToString("e"); //生成 1.234500e+004 12345.ToString("f4"); //生成 12345.0000 12345.ToString("x"); //生成 3039 (16進制) 12345.ToString("p"); //生成 1,234,500.00%