/// <summary>
/// The mciSendString function sends a command string to an MCI device. The device that the command is sent to is specified in the command string.
/// </summary>
/// <param name="lpszCommand">Pointer to a null-terminated string that specifies an MCI command string. For a list, see Multimedia Command Strings.</param>
/// <param name="lpszReturnString">Pointer to a buffer that receives return information. If no return information is needed, this parameter can be NULL.</param>
/// <param name="cchReturn">Size, in characters, of the return buffer specified by the lpszReturnString parameter.</param>
/// <param name="hwndCallback">Handle to a callback window if the "notify" flag was specified in the command string.</param>
/// <returns>Returns zero if successful or an error otherwise. The low-order word of the returned DWORD value contains the error return value. If the error is device-specific, the high-order word of the return value is the driver identifier; otherwise, the high-order word is zero. For a list of possible error values, see MCIERR Return Values.</returns>
[DllImport("winmm.dll", EntryPoint = "mciSendString")]
public static extern int mciSendString(string lpszCommand, string lpszReturnString, uint cchReturn, IntPtr hwndCallback);
mciSendString("Set cdaudio door open wait", "", 0, this.Handle);//打开
mciSendString("Set cdaudio door Closed wait", "", 0, this.Handle);//关闭