String.Format格式说明

导读：
　　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 "[phone]".
　　
　　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%
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本文转自
http://www.cnblogs.com/tuyile006/archive/2006/07/13/449884.aspx