C # string. Format Usage Description

string. Five types of overloads for format:

String. Format (String,object) replaces one or more formatting items in the specified string with the string representation of the specified object.
String. The format (string,object,object) in the specified string is replaced with the string representation of two specified objects.
String. The format (string,object,object) in the specified string is replaced with the string representation of three specified objects.
String. Format (string,params object[]) replaces the formatting item in the specified string with the string representation of the corresponding object in the specified array.
String. Format (system.iformatprovider,string,params object[]) replaces the formatting item in the specified string with the string representation of the corresponding object in the specified array. The specified parameters provide culture-specific formatting information.

commonly used numeric formatting commands:

character	Description	Sample	Output
C	currency	string. Format ("{0:c}", 9)	￥9.00
D	decimal	string. Format ("{0:d}", 9)	9
E	Scientific Count method	string. Format ("{0:e}", 12345)	1.234500E+004
F	decimal	string. Format ("{0:f}", 12345)	12345.00
G	general	string. Format ("{0:g}", 12345)	12345
\ N	A number separated by commas	string. Format ("{0:n}", 12345)	12,345.00
P	percent	string. Format ("{0:p}", 0.12345)	12.35%
X	hex	string. Format ("{0:x}", a)	C
	placeholder	string. Format ("{0:000.000}", 12.3)	012.300

1. Format to monetary form

String.　　　Format ("{0:c}", 9); ￥9.00 (English operating system results: $9.00)
String.　Format ("{0:c1}", 9.67); ￥9.7 (Automatic rounding when intercepting)
String.　　　 Format ("{0:c}", 9); ￥9.00
String.　 Format ("{0:c1}", 9.67); ￥9.7

Format multiple Object objects
String.　Format ("Original price {0:C1}, activity price {1:C3}", 9,7.8666); The original price is ￥9.0, the activity price ￥7.867 2, the format is decimal form (integral type only)

String.　　　　Format ("{0:d}", 9); 9
String.　　　 Format ("{0:d3}", 9); 009, the precision represents the minimum length of the result string
String.　Format ("{0:d3}", 12345); 12345, the result string is not less than the length of the data original degree
String.　　　　Format ("{0:d}", 9); 9
String.　　　 Format ("{0:d3}", 9); 009
String.　Format ("{0:d3}", 12345); 12345 3, format into scientific notation form

String.　Format ("{0:e}", 12345); 1.234500E+004
String. Format ("{0:e3}", 12345); 1.235E+004
String.　Format ("{0:e}", 12345); 1.234500e+004
String. Format ("{0:e3}", 12345); 1.235E+004 4, formatted as a decimal form

String.　Format ("{0:f}", 123.678); 123.68, the default retention of two decimal digits and automatically rounding when intercepted
String. Format ("{0:f3}", 123.678); 123.678
String.　Format ("{0:f}", 123.678); 123.68
String. Format ("{0:f3}", 123.678); 123.678 5, formatted as a regular form

String.　Format ("{0:g}", 12345); 12345
String. Format ("{0:g3}", 12345); 1.23E+04
String.　Format ("{0:g}", 12345); 12345
String. Format ("{0:g3}", 12345); 1.23E+04 6, formatted as a comma-separated number form

String.　Format ("{N}", 12345); 12,345.00, leave two decimal digits by default
String. Format ("{N3}", 12345); 12,345.000
String.　Format ("{n}", 12345); 12,345.00
String. Format ("{n3}", 12345); 12,345.000 7, formatted as a percentage form

String.　Format ("{0:p}", 0.12345); 12.35%, the default retention of two decimal digits and automatically rounding when intercepted
String. Format ("{0:p3}", 0.12345); 12.345%
String.　Format ("{0:p}", 0.12345); 12.35%
String. Format ("{0:p3}", 0.12345); 12.345% 8, formatted as 16 (integer only)

String.　Format ("{0:x}", 12); C
String. Format ("{0:x3}", 12); 00C
String.　Format ("{0:x}", 12); C
String. Format ("{0:x3}", 12); 00C 9, formatted as placeholder form

String.　Format ("{0:000.00}", 12.056); 012.06
String.　Format ("{0:000.00}", 12.003); 012.00
String.　　 Format ("{0:000.00}", 12.3); 012.30
String.　Format ("{0:###.##}", 12.056); 12.06
String.　Format ("{0:###.##}", 12.003); 12
String.　　Format ("{0:###.##}", 12.3); 12.3

Zero placeholder: If the formatted value has a number in the position of "0" in the format string, the number is copied into the result string. The position of the leftmost "0" before the decimal point and the position of the rightmost "0" after the decimal point determine the range of digits that always appear in the result string. The "00" format string causes the value to be rounded to a digit before the decimal point, where 0 is not left out.
Digit placeholder: If the formatted value has a number in the position of "#" in the format string, the number is copied into the result string. Otherwise, no value is stored at this location in the result string. The "# #" format string causes the value to be rounded to a digit before the decimal point, of which 0 is always to be shed.
Note that if "0" is not a valid number, this specifier never displays the "0" character, even if "0" is the only number in the string. If "0" is a valid number in the displayed number, the "0" character is displayed.