driveinfoclass implementation in c#

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace directoryinfo1
{
    public class demoimplement
    {
        public static void copyallfiles(DirectoryInfo source, DirectoryInfo target)
        {
            if (source.FullName.ToLower() == target.FullName.ToLower())
            {
                return;
            }
            if (Directory.Exists(target.FullName) == false)
            {
                Directory.CreateDirectory(target.FullName);
            }
            foreach (FileInfo fi in source.GetFiles())
            {
                Console.WriteLine(@"copying files {0}\{1}", target.FullName, fi.Name);
                fi.CopyTo(Path.Combine(target.ToString(), fi.Name), true);
            }
            foreach (DirectoryInfo disourcesubdir in source.GetDirectories())
            {
                DirectoryInfo nexttargetsubdir = target.CreateSubdirectory(disourcesubdir.Name);
                copyallfiles(disourcesubdir, nexttargetsubdir);
            }
        }
    }
    public class test
    {



        public static void Main(string[] args)
        {

            string sourcedirectory = @"D:\\c#";
            string targetDirectory = @"E:\\tushky";
            DirectoryInfo sourcedir = new DirectoryInfo(sourcedirectory);
            DirectoryInfo targetdir = new DirectoryInfo(targetDirectory);
            copyallfiles(sourcedir,targetdir);
            Console.ReadLine();
            
            
            




        }
    }
}

Error	1	The name 'copyallfiles' does not exist in the current context.