using System;

​

// Class to create analog for JS toFixed method

public static class AnalogForJStoFixed

{

    public static string toFixed(this double number, int decimals)

    {

        return number.ToString("N" + decimals);

    }

}

​

public class Program

{

    public static void Main()

    {

        double d = 235.785;

        // achieve the goal with custom static class created especially to make JS toFixed() method's analog.

        var res1 = d.toFixed(5);

        // without custom class we can just do as follows

        var res2 = d.ToString("N2");

        Console.WriteLine(res1);

        Console.WriteLine(res2);

    }

}