Автор: Baa
WEB-сайт: http://forum.vingrad.ru

Вы уж простите, что на сях... сподручней было :\

//заблокировать 
void CMFcDlg::OnBnClickedButton1() 
{ 
HANDLE hDevice = CreateFile ("\\\\.\\E:",  
 GENERIC_READ, 
 FILE_SHARE_READ | FILE_SHARE_WRITE, 
 NULL, 
 OPEN_EXISTING, 
 NULL, 
 NULL); 
DWORD dwBytesReturned = 0; 
PREVENT_MEDIA_REMOVAL pmr = {TRUE}; 
if(!DeviceIoControl (hDevice, IOCTL_STORAGE_MEDIA_REMOVAL, &pmr, sizeof(pmr),
  NULL, 0, &dwBytesReturned, NULL)) AfxMessageBox ("Door can\'t be locked");
CloseHandle (hDevice); 
} 

//разблокировать
void CMFcDlg::OnBnClickedButton2() 
{ 
HANDLE hDevice = CreateFile ("\\\\.\\E:",  
 GENERIC_READ, 
 FILE_SHARE_READ | FILE_SHARE_WRITE, 
 NULL, 
 OPEN_EXISTING, 
 NULL, 
 NULL); 
DWORD dwBytesReturned = 0; 
PREVENT_MEDIA_REMOVAL pmr = {FALSE}; 
if(!DeviceIoControl (hDevice, IOCTL_STORAGE_MEDIA_REMOVAL, &pmr, sizeof(pmr),
  NULL, 0, &dwBytesReturned, NULL)) AfxMessageBox ("Door can\'t be unlocked");
CloseHandle (hDevice); 
}