using System;

using System.Globalization;

​

public class Program

{

    public static string GetWesternRepresentation(string input, CultureInfo cultureInfo)

    {

        var nativeDigits = cultureInfo.NumberFormat.NativeDigits;

        return input.Replace(cultureInfo.NumberFormat.NumberDecimalSeparator, ".")

                    .Replace(cultureInfo.NumberFormat.NumberGroupSeparator, ",")

                    .Replace(cultureInfo.NumberFormat.NegativeSign, "-")

                    .Replace(cultureInfo.NumberFormat.PositiveSign, "+")

                    .Replace(nativeDigits[0], "0")

                    .Replace(nativeDigits[1], "1")

                    .Replace(nativeDigits[2], "2")

                    .Replace(nativeDigits[3], "3")

                    .Replace(nativeDigits[4], "4")

                    .Replace(nativeDigits[5], "5")

                    .Replace(nativeDigits[6], "6")

                    .Replace(nativeDigits[7], "7")

                    .Replace(nativeDigits[8], "8")

                    .Replace(nativeDigits[9], "9");

    }

​

    public static void Main()

    {

        try

        {

            var culture = new CultureInfo("fa"); // or fa-Ir for Iranian Persian

            string input = "۱۲۳";

            // string input = "١٢٣";    // won't work although looks almost the same

            string output = GetWesternRepresentation(input, culture);

            Console.WriteLine("{0} -> {1}", input, output);

            int number = Int32.Parse(output, CultureInfo.InvariantCulture);

            Console.WriteLine("Value: {0}", number);

        }

        catch (FormatException)

        {

            Console.WriteLine("Bad Format");

        }

        catch (OverflowException)

        {

            Console.WriteLine("Overflow");

        }

    }

}

​