拒绝访问路径'C:\ProgramData\Application Data‘

Question

我想知道文件夹的大小

C:\ProgramData\

我使用以下代码

 public static long GetDirectorySize(string folderPath)
        {
            DirectoryInfo di = new DirectoryInfo(folderPath);
            return di.EnumerateFiles("*", SearchOption.AllDirectories).Sum(fi => fi.Length);
        }

但它会提示我错误：

An unhandled exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll

Additional information: Access to the path 'C:\ProgramData\Application Data' is denied.

我已经设置了

<requestedExecutionLevel  level="requireAdministrator" uiAccess="false" />

在app.manifest中。似乎即使我直接在windows中打开C:\ProgramData\Application Data，它也会被拒绝。

如何解决这个问题？

Answer 1

我想你不能这样做，命令如下：

C:\ProgramData>dir /a
Volume in drive C is OSDisk
Volume Serial Number is 067E-828E

Directory of C:\ProgramData

04/20/2017  02:00 PM    <DIR>          .
04/20/2017  02:00 PM    <DIR>          ..
07/14/2009  01:08 PM    <JUNCTION>     Application Data [C:\ProgramData]

您可以看到，应用程序数据是指向ProgramData的连接点。Windows包括许多类似的连接点，以便向后兼容较旧的应用程序。

交叉点上的安全权限明确禁止列出文件，这就是为什么您无法获得其内容的列表：

C:\ProgramData>icacls "Application Data" /L
Application Data Everyone:(DENY)(S,RD)
                 Everyone:(RX)
                 NT AUTHORITY\SYSTEM:(F)
                 BUILTIN\Administrators:(F)

有关更多信息，请访问：What is the Programdata/Application Data folder?

Answer 2

由于某些原因，在文件系统上枚举可能会引发SecurityException。

最好的选择是对这些异常进行回调。

public class FileSytemInfoErrorArgs
{
    public FileSytemInfoErrorArgs( FileSystemInfo fileSystemInfo, Exception error )
    {
        FileSystemInfo = fileSystemInfo;
        Error = error;
    }

    public FileSystemInfo FileSystemInfo { get; }
    public Exception Error { get; }
    public bool Handled { get; set; }
}

public static class DirectoryInfoExtensions
{
    public static long GetTotalSize( this DirectoryInfo di, Action<FileSytemInfoErrorArgs> errorAction = null )
    {
        long size = 0;

        foreach ( var item in di.EnumerateFileSystemInfos() )
        {
            try
            {
                size += ( item as FileInfo )?.Length
                    ?? ( item as DirectoryInfo )?.GetTotalSize( errorAction )
                    ?? throw new InvalidOperationException();
            }
            catch ( Exception ex )
            {
                var arg = new FileSytemInfoErrorArgs( item, ex );
                errorAction?.Invoke( arg );
                if ( !arg.Handled )
                {
                    throw;
                }
            }
        }

        return size;
    }
}

最后

var path = Environment.GetFolderPath( Environment.SpecialFolder.CommonApplicationData );
var dir = new DirectoryInfo( path );
var totalSize = dir.GetTotalSize(
    errorAction: e =>
    {
        // Console.WriteLine( "{0}: {1}", e.FileSystemInfo.FullName, e.Error.Message );
        e.Handled = true;
    } );