Uploading Large Files via FTP by Threading

private void uploadButton_Click(object sender, EventArgs e)
{
     if (ofd_psUpdate.ShowDialog() == DialogResult.OK)
     {
          thread = new Thread(UploadFile);
          thread.Start();
     }
}

private void UploadFile(object obj)
{
     try
     {                
          FtpWebRequest request = (FtpWebRequest)FtpWebRequest.Create("ftpURL" + ofd_psUpdate.SafeFileName);
          request.Method = WebRequestMethods.Ftp.UploadFile;
          request.Credentials = new NetworkCredential(ftpUserNameTextBox.Text.Trim(), ftpPasswordTextBox.Text.Trim());
          request.UsePassive = true;
          request.UseBinary = true;
          request.KeepAlive = true;

          stream = File.OpenRead(ofd_psUpdate.FileName);
          byte[] buffer = new byte[stream.Length];
          int bytesSize = 0;

          reqStream = request.GetRequestStream();

          while ((bytesSize = stream.Read(buffer, 0, buffer.Length)) > 0)
          {
               reqStream.Write(buffer, 0, bytesSize);
               this.Invoke(new UpdateProgessCallback(this.UpdateProgress), new object[] { reqStream.Length, stream.Length });
          }                
     }
     catch (Exception ex)
     {
          MessageBox.Show("Fail\n\n" + ex.Message);
     }
     finally
     {
          //reqStream.Close();
          //stream.Close();
     }
}

private void UpdateProgress(Int64 BytesRead, Int64 TotalBytes)
{
     // Calculate the download progress in percentages
     PercentProgress = Convert.ToInt32((BytesRead * 100) / TotalBytes);
     // Make progress on the progress bar
     progressBar1.Value = PercentProgress;
     // Display the current progress on the form
     label20.Text = "Uploaded " + BytesRead + " of " + TotalBytes + " (" + PercentProgress + "%)";
}