      private void Select_Device(string ext)
        {
            if (ext == "WAV")
            {
                axMMControl1.DeviceType = "WaveAudio";
                pictureBox1.Visible = false;
            }
            else if (ext == "AVI")
            {
                axMMControl1.DeviceType = "AviVideo";
                pictureBox1.Visible = true;
            }
            else if (ext == "MMM")
            {
                axMMControl1.DeviceType = "MMMovie";
                pictureBox1.Visible = true;
            }
        }

   