string.format大全

字符串的数字格式

stringstr1 =string.Format("{0:N1}",56789);               //result: 56,789.0
stringstr2 =string.Format("{0:N2}",56789);               //result: 56,789.00
stringstr3 =string.Format("{0:N3}",56789);               //result: 56,789.000
stringstr8 =string.Format("{0:F1}",56789);               //result: 56789.0
stringstr9 =string.Format("{0:F2}",56789);               //result: 56789.00
stringstr11 =(56789 / 100.0).ToString("#.##");           //result: 567.89
stringstr12 =(56789 / 100).ToString("#.##");             //result: 567

C 或 c
货币
Console.Write("{0:C}", 2.5); / 2.50
Console.Write("{0:C}", -2.5); //($2.50)

D 或 d
十进制数
Console.Write("{0:D5}", 25); //00025

E 或 e
科学型
Console.Write("{0:E}", 250000); //2.500000E+005

F 或 f
固定点
Console.Write("{0:F2}", 25); //25.00
Console.Write("{0:F0}", 25); //25

G 或 g
常规
Console.Write("{0:G}", 2.5); //2.5

N 或 n
数字
Console.Write("{0:N}", 2500000); //2,500,000.00

X 或 x
十六进制
Console.Write("{0:X}", 250); //FA
Console.Write("{0:X}", 0xffff); //FFFF
/////////////////////////////////////////////////////////////////////////////////
C#格式化数值结果表

字符
    

说明
    

示例
    

输出
C     货币     string.Format("{0:C3}", 2)     $2.000
D     十进制     string.Format("{0:D3}", 2)     002
E     科学计数法     1.20E+001     1.20E+001
G     常规     string.Format("{0:G}", 2)     2
N     用分号隔开的数字     string.Format("{0:N}", 250000)     250,000.00
X     十六进制     string.Format("{0:X000}", 12)     C

    
    string.Format("{0:000.000}", 12.2)     012.200
Strings

There really isn't any formatting within a strong, beyond it's alignment. Alignment works for any argument being printed in a String.Format call.

 

Sample     Generates
String.Format("->{1,10}<-", "Hello");     -> Hello<-
String.Format("->{1,-10}<-", "Hello");     ->Hello <-

Numbers

Basic number formatting specifiers:

 

Specifier     Type     Format     

Output
(Passed
Double 1.42)
    

Output
(Passed
Int -12400)
c     Currency     {0:c}     $1.42     -$12,400
d     Decimal (Whole number)     {0:d}     System.
FormatException     -12400
e     Scientific     {0:e}     1.420000e+000     -1.240000e+004
f     Fixed point     {0:f}     1.42     -12400.00
g     General     {0:g}     1.42     -12400
n     Number with commas for thousands     {0:n}     1.42     -12,400
r     Round trippable     {0:r}     1.42     System.
FormatException
x     Hexadecimal     {0:x4}     System.
FormatException     cf90

Custom number formatting:

 

Specifier     Type     Example     Output (Passed Double 1500.42)     Note
0     Zero placeholder     {0:00.0000}     1500.4200     Pads with zeroes.
#     Digit placeholder     {0:(#).##}     (1500).42     
.     Decimal point     {0:0.0}     1500.4     
,     Thousand separator     {0:0,0}     1,500     Must be between two zeroes.
,.     Number scaling     {0:0,.}     2     Comma adjacent to Period scales by 1000.
%     Percent     {0:0%}     150042%     Multiplies by 100, adds % sign.
e     Exponent placeholder     {0:00e+0}     15e+2     Many exponent formats available.
;     Group separator     see below     
    

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".

     

    变量.ToString()


    字符型转换 转为字符串
    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进制)
    12345.ToString("p"); //生成 1,234,500.00%