1 class Program 2     { 3         static void Main(string[] args) 4         { 5             //retrieve current culture info by cloning it so that 6             //we can manipulate its NumberFormat member 7             CultureInfo ci = Thread.CurrentThread.CurrentCulture.Clone() as CultureInfo; 8             NumberFormatInfo nfi = ci.NumberFormat; 9 10             //set "123456" to "123|456*"11             nfi.CurrencyPositivePattern = 1;12             nfi.CurrencyGroupSeparator = "|";13             nfi.CurrencySymbol = "*";14             nfi.CurrencyDecimalDigits = 0;15             //reset the NumberFormat16             ci.NumberFormat = nfi;17             //set the thread culture to our modified CultureInfo18             Thread.CurrentThread.CurrentCulture = ci;19             Console.WriteLine(123456.ToString("C"));20             //"C" indicate use Currency format21         }22     }

 

　and the interval ：every three digits.