สอบถามปัญหาการใช้งาน Plugin ของ VLC ไม่สามารถเล่น วิดิโอได้

private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog1 = new OpenFileDialog();
            openFileDialog1.Filter = " (*.mp4;*.mp3;*.m3u8;)|*.mp4;*.mp3;*.m3u8;";
            if(openFileDialog1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
              //  axVLCPlugin21.playlist.add(openFileDialog1.FileName,openFileDialog1.SafeFileName,null);

                this.textBox1.Text = openFileDialog1.FileName;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
           // axVLCPlugin21.playlist.prev();
            axWindowsMediaPlayer1.URL = textBox1.Text;
            axWindowsMediaPlayer1.Ctlcontrols.play();


        }

        private void button3_Click(object sender, EventArgs e)
        {
            //axVLCPlugin21.playlist.stop();
            axWindowsMediaPlayer1.Ctlcontrols.stop();

        }

        private void button4_Click(object sender, EventArgs e)
        {
           // axVLCPlugin21.playlist.togglePause();
            axWindowsMediaPlayer1.Ctlcontrols.pause();

        }