This example shows how to open and close the tray of the CD drive. First we will need to define the following function that will be opening the disk tray:

        [DllImport("winmm.dll", EntryPoint = "mciSendString")]
        public static extern int mciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);

Usage:

            //To open
            int result = mciSendString("set cdaudio door open", null, 0, 0);

            //To close
            result = mciSendString("set cdaudio door closed", null, 0, 0);