获取磁盘上文件的大小

它使用ho1建议的GetCompressedFileSize，以及PaulStack建议的GetDiskFreeSpace，但是使用P /
Invoke。我仅对压缩文件进行了测试，我怀疑它对零碎文件不起作用。

    public static long GetFileSizeonDisk(string file)    {        FileInfo info = new FileInfo(file);        uint dummy, sectorsPerCluster, bytesPerSector;        int result = GetDiskFreeSpaceW(info.Directory.Root.FullName, out sectorsPerCluster, out bytesPerSector, out dummy, out dummy);        if (result == 0) throw new Win32Exception();        uint clusterSize = sectorsPerCluster * bytesPerSector;        uint hosize;        uint losize = GetCompressedFileSizeW(file, out hosize);        long size;        size = (long)hosize << 32 | losize;        return ((size + clusterSize - 1) / clusterSize) * clusterSize;    }    [Dllimport("kernel32.dll")]    static extern uint GetCompressedFileSizeW([In, MarshalAs(UnmanagedType.LPWStr)] string lpFileName,       [Out, MarshalAs(UnmanagedType.U4)] out uint lpFileSizeHigh);    [Dllimport("kernel32.dll", SetLastError = true, PreserveSig = true)]    static extern int GetDiskFreeSpaceW([In, MarshalAs(UnmanagedType.LPWStr)] string lpRootPathName,       out uint lpSectorsPerCluster, out uint lpBytesPerSector, out uint lpNumberOfFreeClusters,       out uint lpTotalNumberOfClusters);