Reverse A String In C#.NET

using System;
namespace Learn {
    class Program {
        static void Main(string[] args) {
            string Str, Revstr = "";
            int Length;
            Console.Write("Enter A String : ");
            Str = Console.ReadLine();
            Length = Str.Length - 1;
            while (Length >= 0) {
                Revstr = Revstr + Str[Length];
                Length--;
            }
            Console.WriteLine("Reverse String Is {0}", Revstr);
            Console.ReadLine();
        }
    }
}