VC++ 利用窗口化命令打开、关闭光驱，好像只能用一次，也就是第一次打开是有效的，再次打开就没有用了，仔细研究一下吧。 -VC++ use of windowing commands to open and close the CD-ROM drive, if only be used once, which is the first to open is effective, and turn it on again, carefully study it.