RegularExpressions

 

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleApplication2
{
    class Program
    {

        static void Main(string[] args)
        {
            string Pattern = "^[0-9]*$";

            bool flag = Regex.IsMatch("0070044244", Pattern);

            if (flag == true)
                Console.WriteLine("Right");
            else
                Console.WriteLine("Wrong");
            Console.Read();
          

        }
    }
}