NumberStyles and BigInteger parse
using System; using System.Globalization; using System.Numerics; public class Example { public static void Main() { BigInteger number; number = BigInteger.Parse(" -6 ", NumberStyles.Integer); Console.WriteLine(number); number = BigInteger.Parse("6", NumberStyles.AllowHexSpecifier); Console.WriteLine(number); try { number = BigInteger.Parse(" -6 ", NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite); Console.WriteLine(number); } catch (FormatException e) { Console.WriteLine(e.Message); } try { number = BigInteger.Parse(" 99999 ", NumberStyles.AllowLeadingSign); Console.WriteLine(number); } catch (FormatException e) { Console.WriteLine(e.Message); } } }