获取磁盘上的文件大小

Question

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

这给出了文件的逻辑大小，而不是磁盘上的大小。

我希望得到C＃中磁盘上的文件大小（最好不包括interop），正如Windows资源管理器报告的那样。

应该给予正确的尺寸，包括：

• 一个压缩文件
• 稀疏文件
• 碎片文件

Answer 1

这个使用GetCompressedFileSize，就像ho1建议的那样，还有GetDiskFreeSpace，因为PaulStack建议使用 ，但是它的确使用了P/Invoke。我只对压缩文件进行过测试，我怀疑它不适用于碎片文件。

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); 

Answer 2

根据MSDN社会论坛：

磁盘上的大小应该是存储文件的簇的大小：
http://social.msdn.microsoft.com/Forums/en-US/Vsexpressvcs/thread/85bf76ac-a254-41d4-a3d7-e7803c8d9bc3
您需要进入P/Invoke以查找簇大小; GetDiskFreeSpace（）返回它。

请参阅How to get the size on disk of a file in C#。

但是请注意，在打开压缩的NTFS中这不起作用。

Answer 3

上面的代码不正确的Windows Server 2008或2008 R2或Windows   7和Windows簇大小始终为零工作 基于Windows Vista系统（GetDiskFreeSpaceW和GetDiskFreeSpace返回-1甚至UAC禁用。）下面是修改后的代码有效。

C＃

public static long GetFileSizeOnDisk(string file) 
{ 
    FileInfo info = new FileInfo(file); 
    uint clusterSize; 
    using(var searcher = new ManagementObjectSearcher("select BlockSize,NumberOfBlocks from Win32_Volume WHERE DriveLetter = '" + info.Directory.Root.FullName.TrimEnd('\\') + "'") { 
     clusterSize = (uint)(((ManagementObject)(searcher.Get().First()))["BlockSize"]); 
    } 
    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); 

VB.NET

Private Function GetFileSizeOnDisk(file As String) As Decimal 
     Dim info As New FileInfo(file) 
     Dim blockSize As UInt64 = 0 
     Dim clusterSize As UInteger 
     Dim searcher As New ManagementObjectSearcher(_ 
      "select BlockSize,NumberOfBlocks from Win32_Volume WHERE DriveLetter = '" + _ 
      info.Directory.Root.FullName.TrimEnd("\") + _ 
      "'") 

     For Each vi As ManagementObject In searcher.[Get]() 
      blockSize = vi("BlockSize") 
      Exit For 
     Next 
     searcher.Dispose() 
     clusterSize = blockSize 
     Dim hosize As UInteger 
     Dim losize As UInteger = GetCompressedFileSizeW(file, hosize) 
     Dim size As Long 
     size = CLng(hosize) << 32 Or losize 
     Dim bytes As Decimal = ((size + clusterSize - 1)/clusterSize) * clusterSize 

     Return CDec(bytes)/1024 
    End Function 

    <DllImport("kernel32.dll")> _ 
    Private Shared Function GetCompressedFileSizeW(_ 
     <[In](), MarshalAs(UnmanagedType.LPWStr)> lpFileName As String, _ 
     <Out(), MarshalAs(UnmanagedType.U4)> lpFileSizeHigh As UInteger) _ 
     As UInteger 
    End Function 

Answer 4

我认为这将是这样的：

double ifileLength = (finfo.Length/1048576); //return file size in MB .... 

我仍然在做一些测试这，以获得确认。