获取磁盘有效空间，空闲空间以及总空间大小

ULONGLONG CHKVisionDlg::GetDiskSpace(LPCTSTR DriverName, int Style)
{
   ULONGLONG SpaceSize;

  ULARGE_INTEGER nFreeBytesAvailable;
  ULARGE_INTEGER nTotalNumberOfBytes;
  ULARGE_INTEGER nTotalNumberOfFreeBytes;
  ULARGE_INTEGER ALargeInteger;

 
  GetDiskFreeSpaceEx(DriverName,     &nFreeBytesAvailable,
               &nTotalNumberOfBytes,     &nTotalNumberOfFreeBytes);
 
  switch(Style)
  {
  case 0:
   {
    ALargeInteger=nFreeBytesAvailable;//磁盘有效空间
    break;
   }
  case 1:
   {

    ALargeInteger=nTotalNumberOfBytes;//磁盘总的空间
    break;
   }
  case 2:
   {
    ALargeInteger=nTotalNumberOfFreeBytes;//磁盘空闲的空间

    break;
   }

  }
  //转换为M的单位
  ALargeInteger.QuadPart<<20;
  SpaceSize=ALargeInteger.QuadPart;
  return SpaceSize;
}