Question

I’m trying to parse a string to a decimal and the parsing should failed if there are more than 2 digits after the decimal point in the string.

e.g:

1.25 is valid but 1.256 is invalid.

I tried to use the decimal.TryParse method in C# to solve in the following manner but this does not help…

NumberFormatInfo nfi = new NumberFormatInfo();
nfi.NumberDecimalDigits = 2;
if (!decimal.TryParse(test, NumberStyles.AllowDecimalPoint, nfi, out s))
{
    Console.WriteLine("Failed!");
    return;
}            
Console.WriteLine("Passed");

Any suggestions?

Answer 1

Have a look at Regex. There are various threads covering this subjects.

example:
Regex to match 2 digits, optional decimal, two digits

Regex decimalMatch = new Regex(@"[0-9]?[0-9]?(\.[0-9]?[0-9]$)"); this should do in your case.

   var res = decimalMatch.IsMatch("1111.1"); // True
  res = decimalMatch.IsMatch("12111.221"); // False
  res = decimalMatch.IsMatch("11.21"); // True
  res = decimalMatch.IsMatch("11.2111"); // False
  res = decimalMatch.IsMatch("1121211.21143434"); // false