using System;

public class Program

{

    public static void Main()

    {

        decimal decimalNumber;

        //string number = null; // -> 0 invalid format

        //string number = ""; // -> 0 invalid format

        //string number = "123,.456,78"; // -> 0 invalid format

        string number = "123.456,78"; // -> 123.456,78 US format

        //string number = "123,456.78"; // -> 123.456,78 NL format

        //string number = "123,450.001"; // -> 123.450

        //string number = "123,450.005"; // -> 123.450,01

        if (!Decimal.TryParse(number, System.Globalization.NumberStyles.Any, new System.Globalization.CultureInfo("en-US"), out decimalNumber))

            if (!Decimal.TryParse(number, System.Globalization.NumberStyles.Any, new System.Globalization.CultureInfo("nl-NL"), out decimalNumber))

                decimalNumber = 0; //throw error?

                // N2 adds group separators (periods) in the thousands place etc

        var euFormatNumber = decimalNumber.ToString("N2", new System.Globalization.CultureInfo("nl-NL"));

        Console.WriteLine(euFormatNumber.Replace(",00", ""));

    }

}