WinApp C# วิธีลบไฟล์ซ้ำแบบบ้านๆ

string strRegex = @"(.*?[\[\(]\d{1,}[\]\)].mp4)";

 private void button1_Click(object sender, EventArgs e)
        {
            using (FolderBrowserDialog fol = new FolderBrowserDialog()) { fol.ShowDialog(); textBox1.Text = fol.SelectedPath; }
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            string strRegex = @"(.*?[\[\(]\d{1,}[\]\)].mp4)";
            foreach (string file in System.IO.Directory.GetFiles(textBox1.Text, "*.*", System.IO.SearchOption.AllDirectories))
            {
                if (new Regex(strRegex, RegexOptions.None).IsMatch(file))
                {
                    string f = new Regex(@"[\[\(]\d{1,}[\]\)]", RegexOptions.None).Replace(file, "");
                    if (System.IO.File.Exists(f))
                    {
                        System.IO.File.Delete(file);
                    }
                }
            }
            MessageBox.Show("Complete .....");
        }