下面代码将实现打开关闭CD/DVD：

using System.Runtime.InteropServices;  using System.Text;  ...  public static void Main( )  {     int result = mciSendString         ("set cdaudio door open", null, 0, IntPtr.Zero);     result =         mciSendString ("set cdaudio door closed",         null, 0, IntPtr.Zero);  }    [DllImport("winmm.dll", EntryPoint="mciSendStringA", CharSet=CharSet.Ansi)]  protected static extern int mciSendString     (string mciCommand,     StringBuilder returnValue,     int returnLength,     IntPtr callback);