using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        string displayValue = "000000000001";

        int decdigits = 3;

        displayValue =  displayValue.TrimStart(new Char[] { '0' }).PadLeft(1,'0');

​

        if (displayValue.Length >= decdigits )

            displayValue = displayValue

                    .Insert(displayValue.Length - decdigits , ".");

        else

            displayValue = displayValue

                    .Insert(0, "0." + new string('0', decdigits - displayValue.Length));

         if (displayValue.First() == '.')

            displayValue = displayValue.Insert(0, "0");

        Console.WriteLine("Display value: {0}", displayValue);

    }

}