1 class Program
2 {
3 static void Main(string[] args)
4 {
5 var integer = 10000;
6 var decimals = 10000.12345;
7 var percent = 0.12345;
8
9 //四舍五入保留N位小数,默认保留两位小数
10 Console.WriteLine("{0}.ToString(\"0\") = {1}".FormatWith(integer, integer.ToString("0.00"))); //10000.00
11 Console.WriteLine("{0}.ToString(\"0.00\") = {1}".FormatWith(integer, integer.ToString("0.00"))); //10000.00
12 Console.WriteLine("{0}.ToString(\"0.00\") = {1}".FormatWith(decimals, decimals.ToString("0.00"))); //10000.12
13 Console.WriteLine("{0}.ToString(\"0.00000\") = {1}".FormatWith(decimals, decimals.ToString("0.0000"))); //10000.1235
14 Console.WriteLine();
15
16 //四舍五入保留N位小数,默认保留两位小数
17 Console.WriteLine("{0}.ToString(\"F\") = {1}".FormatWith(integer, integer.ToString("F"))); //10000.00
18 Console.WriteLine("{0}.ToString(\"F2\") = {1}".FormatWith(integer, integer.ToString("F2"))); //10000.00
19 Console.WriteLine("{0}.ToString(\"F2\") = {1}".FormatWith(decimals, decimals.ToString("F2"))); //10000.12
20 Console.WriteLine("{0}.ToString(\"F4\") = {1}".FormatWith(decimals, decimals.ToString("F4"))); //10000.1235
21 Console.WriteLine();
22
23 //以千分位分隔数字,四舍五入保留N位小数,默认保留两位小数
24 Console.WriteLine("{0}.ToString(\"N\") = {1}".FormatWith(integer, integer.ToString("N"))); //10,000.00
25 Console.WriteLine("{0}.ToString(\"N2\") = {1}".FormatWith(integer, integer.ToString("N2"))); //10,000.00
26 Console.WriteLine("{0}.ToString(\"N2\") = {1}".FormatWith(decimals, decimals.ToString("N2"))); //10,000.12
27 Console.WriteLine("{0}.ToString(\"N4\") = {1}".FormatWith(decimals, decimals.ToString("N4"))); //10,000.1235
28
29 //以百分比表示数字,四舍五入保留N位小数,默认保留两位小数
30 Console.WriteLine("{0}.ToString(\"P\") = {1}".FormatWith(percent, percent.ToString("P"))); //12.35%
31 Console.WriteLine("{0}.ToString(\"P1\") = {1}".FormatWith(percent, percent.ToString("P1"))); //12.3%
32 Console.WriteLine("{0}.ToString(\"P2\") = {1}".FormatWith(percent, percent.ToString("P2"))); //12.35%
33
34 Console.ReadKey();
35 }
36 }
![](https://images2017.cnblogs.com/blog/1163283/201707/1163283-20170728180621102-1031489783.jpg)