如何用逗号格式化数字？

Question

int a = 10000000;
a.ToString();

How do I make the output?

10,000,000

Answer 1

尝试将N0为无小数部分：

string formatted = a.ToString("N0"); // 10,000,000

Answer 2

You can also do String.Format:

int x = 100000;
string y = string.Empty;
y = string.Format("{0:#,##0.##}", x); 
//Will output: 100,000

If you have decimal, the same code will output 2 decimal places:

double x = 100000.2333;
string y = string.Empty;
y = string.Format("{0:#,##0.##}", x); 
//Will output: 100,000.23

To make comma instead of decimal use this:

double x = 100000.2333;
string y = string.Empty;
y = string.Format(System.Globalization.CultureInfo.GetCultureInfo("de-DE"), "{0:#,##0.##}", x);

Answer 3

a.ToString("N0")

另请参阅： MSDN中的标准数字格式字符串

Answer 4

A simpler String.Format option:

int a = 10000000;
String.Format("{0:n0}", a); //10,000,000

Answer 5

a.tostring（“ 00,000,000”）