.net 获取磁盘上文件的大小

发布于09月20日

var length = new System.IO.FileInfo(path).Length;

这会给出文件的逻辑大小，而不是磁盘上的大小.

我希望获得Windows资源管理器报告的磁盘上文件的大小(最好没有interop).

它应该给出正确的尺寸，包括:

压缩文件
稀疏的文件
零碎的文件

推荐答案

按照ho1的建议，它使用GetCompressedFileSize，以及GetDiskFreeSpace

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);