private void button2_Click(object sender, EventArgs e)
        {

            foreach (string IDdir in Directory.GetDirectories(textBox1.Text)) 
                {
                    FileList.Clear();
                    sb1 = new StringBuilder();
                    //add loging
                    sb1.Append("Directory: " + IDdir.ToString() + Environment.NewLine);
                    //Console.WriteLine("Directory: " + IDdir.ToString());
                    foreach (string subdir in Directory.GetDirectories(IDdir)) 
                        {
                             sb1.Append("Subdir: " + subdir.ToString() + Environment.NewLine);


                            foreach (string csvfile in Directory.GetFiles(subdir, "*.csv")) 
                            {
                                 sb1.Append( "Adding File :  " + csvfile.ToString() + "to filelist" + Environment.NewLine);
                                FileList.Add(csvfile);
                            }
                        }
                    
                }
            sb1.Append("Files in Filelist: " + FileList.Count.ToString() + Environment.NewLine);
            textBox2.Invoke(new UpdateTextCallback(this.AddText), sb1.ToString());
            backwork.RunWorkerAsync(FileList);
        }