C# Auto update program

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace UpdateVersion
{
    public partial class Form1 : Form
    {
        List<string> listFiles = new List<string>();
        double countFiles = 0.0;
        public Form1()
        {
            InitializeComponent();
        }   
        private void Form1_Load(object sender, EventArgs e)
        {         
            backgroundWorker1.RunWorkerAsync();
        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            listFiles = CopyFolder("D:\\Datas", "D:\\Backup");
            countFiles = 100.0 / listFiles.Count;

            for(int i=1;i<=listFiles.Count;i++)
            {           
                backgroundWorker1.ReportProgress(i);
                if (i == listFiles.Count)
                    Thread.Sleep(500);
                Thread.Sleep(50);
            }
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBarValue.Value = (int)(countFiles * e.ProgressPercentage);
            this.label1.Text = "Update to "+ listFiles[e.ProgressPercentage-1].ToString();       
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            this.label1.Text = "Update completed!!!!";
            Thread.Sleep(1000);
          //  Process.Start("D:\\Backup\\UpdateVersion.exe");
            Application.Exit();

        }
        static public List<string> CopyFolder(string sourceFolder, string destFolder)
        {
            List<string> listfile = new List<string>();
            if (!Directory.Exists(destFolder))
                Directory.CreateDirectory(destFolder);
            string[] files = Directory.GetFiles(sourceFolder);
            foreach (string file in files)
            {
                string name = Path.GetFileName(file);
                string dest = Path.Combine(destFolder, name);

                File.Copy(file, dest,true);
                listfile.Add(dest);
            }
            string[] folders = Directory.GetDirectories(sourceFolder);
            foreach (string folder in folders)
            {
                string name = Path.GetFileName(folder);
                string dest = Path.Combine(destFolder, name);
                CopyFolder(folder, dest);
                listfile.Add(dest);
            }
            return listfile;
        }     
    }
}