using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        double price = 57.991;

        Console.WriteLine("Orjinal: " + price.ToString());

        Console.WriteLine("N3     : " + price.ToString("N3"));

        Console.WriteLine("N2     : " + price.ToString("N2"));

        Console.WriteLine("Ünlü   : " + price.ToUnluPrice());

        string priceStr = price.ToUnluPrice();

        double test = 0;

        double test2 = 0;

        double.TryParse(priceStr, out test);

        try { test2 = Convert.ToDouble(priceStr); } catch { }

        Console.WriteLine(test.ToString());

        Console.WriteLine(test2.ToString());

    }   

}

​

public static class Extensions

{

    public static string ToUnluPrice(this double val)

    {

        string result = val.ToString("N3");

        result = Regex.Replace(result, "\\.*0$", " ");

        return result;

    }

}