文件名以句点结尾并使用FileInfo C＃

时间：2017-03-30 04:22:13

标签： c# file-exists system.io.fileinfo

我遇到的问题是FileInfo无法看到名称末尾包含句点的文件。我知道Windows会以这种方式阻止命名文件，但这些数据来自不同的操作系统。

我可以使用命令行在Windows中创建问题文件：

echo "test" > "\\?\C:\Test\BadFileName."

这是我用来测试文件的代码：

DateTime origAccessDate;
DateTime OrigCreateDate;
long sizeBytes;

string path = @"\\?\C:\Test\BadFileName.";
FileInfo fi = new FileInfo(path);

try
{
     origAccessDate = fi.LastAccessTime;
     OrigCreateDate = fi.CreationTime;
     sizeBytes = fi.Length;
}
catch (Exception ex)
{
     MessageBox.Show(ex.Message);
}

在路径上调用FileInfo时会出现问题。即使您可以复制/粘贴路径以确认其有效，Exists属性也是false。目标不是重命名文件以便阅读，而是按原样（原样）阅读。

3 个答案:

答案 0 :(得分：0)

由于这显然是不受支持的情况，我怀疑如果不使用某些低级文件访问就可以完成。

你可以尝试做的是放弃FileInfo并继续 File.Exists(path)和File.ReadAllBytes(path)。 这些可能能够绕过这个问题。

使用SafeFileHandle进行文件访问

以下是未经测试的

创建UnmanagedFileLoader的实例（下面的代码，取自MSDN），允许您创建一个SafeFileHandle对象，该对象可以传递给FileStream中的UnmanagedFileLoader ufl = new UnmanagedFileLoader(path); FileStream fs = new FileStream(ufl.Handle, FileMode.Open); 构造函数。以下方式：

ufl.Handle.Dispose()

注意：请记得致电 class UnmanagedFileLoader { public const short FILE_ATTRIBUTE_NORMAL = 0x80; public const short INVALID_HANDLE_VALUE = -1; public const uint GENERIC_READ = 0x80000000; public const uint GENERIC_WRITE = 0x40000000; public const uint CREATE_NEW = 1; public const uint CREATE_ALWAYS = 2; public const uint OPEN_EXISTING = 3; // Use interop to call the CreateFile function. // For more information about CreateFile, // see the unmanaged MSDN reference library. [DllImport("kernel32.dll", SetLastError = true, CharSet=CharSet.Unicode)] static extern SafeFileHandle CreateFile(string lpFileName, uint dwDesiredAccess, uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile); private SafeFileHandle handleValue = null; public UnmanagedFileLoader(string Path) { Load(Path); } public void Load(string Path) { if (Path == null || Path.Length == 0) { throw new ArgumentNullException("Path"); } // Try to open the file. handleValue = CreateFile(Path, GENERIC_WRITE, 0, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero); // If the handle is invalid, // get the last Win32 error // and throw a Win32Exception. if (handleValue.IsInvalid) { Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error()); } } public SafeFileHandle Handle { get { // If the handle is valid, // return it. if (!handleValue.IsInvalid) { return handleValue; } else { return null; } } } } 。

这应该会给你一个更多的，我们可以说，直接访问该文件，因此绕过Windows实施的有效文件名的执行。

  

UnmanagedFileLoader代码

GetFileTimeSample

使用Windows API访问文件日期

以下GetFileTime类取自www.pinvoke.net，使用另一个Windows API调用，特别是DateTime fileDateCreated; DateTime fileDateAccessed; DateTime fileDateModified; GetFileTimeSample.GetFileTimes(path, out fileDateCreated, out fileDateAccessed, out fileDateModified); 。 这个实现只是一个例子，你肯定能够调整它只获得你需要的日期。在目前的形式中，它将输出所有三个日期。

用法：

out

从C＃7.0开始，可以直接在函数调用中声明GetFileTimeSample.GetFileTimes(path, out DateTime fileDateCreated, out DateTime fileDateAccessed, out DateTime fileDateModified); 变量，如下所示：

public class GetFileTimeSample
{
    private const uint GENERIC_READ = 0x80000000;
    private const uint FILE_SHARE_READ = 0x1;
    private const uint FILE_ATTRIBUTE_NORMAL = 0x80;
    private const int INVALID_HANDLE_VALUE = -1;
    private const uint OPEN_EXISTING = 3;

    [StructLayout(LayoutKind.Sequential)]
    private struct FILETIME
    {
    public uint dwLowDateTime;
    public uint dwHighDateTime;
    }

    [DllImport("kernel32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CloseHandle(
    IntPtr hObject
    );

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
    private static extern IntPtr CreateFile(
    string lpFileName,
    uint dwDesiredAccess,
    uint dwShareMode,
    IntPtr SecurityAttributes,
    uint dwCreationDisposition,
    uint dwFlagsAndAttributes,
    IntPtr hTemplateFile
    );

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool GetFileTime(
    IntPtr hFile,
    ref FILETIME lpCreationTime,
    ref FILETIME lpLastAccessTime,
    ref FILETIME lpLastWriteTime
    );

    public static void GetFileTimes(string FileName, out DateTime CreationTime, out DateTime LastAccessTime, out DateTime LastWriteTime)
    {
    CreationTime = DateTime.MinValue;
    LastAccessTime = DateTime.MinValue;
    LastWriteTime = DateTime.MinValue;
    IntPtr ptr = IntPtr.Zero;
    FILETIME ftCreationTime = new FILETIME();
    FILETIME ftLastAccessTime = new FILETIME();
    FILETIME ftLastWriteTime = new FILETIME();
    try
    {
        ptr = CreateFile(FileName, GENERIC_READ, FILE_SHARE_READ, IntPtr.Zero, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, IntPtr.Zero);
        if (ptr.ToInt32() == INVALID_HANDLE_VALUE)
        Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
        if (GetFileTime(ptr, ref ftCreationTime, ref ftLastAccessTime, ref ftLastWriteTime) != true)
        Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
        CreationTime = DateTime.FromFileTimeUtc((((long)ftCreationTime.dwHighDateTime) << 32) | ((uint)ftCreationTime.dwLowDateTime));
        LastAccessTime = DateTime.FromFileTimeUtc((((long)ftLastAccessTime.dwHighDateTime) << 32) | ((uint)ftLastAccessTime.dwLowDateTime));
        LastWriteTime = DateTime.FromFileTimeUtc((((long)ftLastWriteTime.dwHighDateTime) << 32) | ((uint)ftLastWriteTime.dwLowDateTime));
    }
    catch (Exception e)
    {
        throw (e);
    }
    finally
    {
        if (ptr !=IntPtr.Zero && ptr.ToInt32() != INVALID_HANDLE_VALUE) CloseHandle(ptr);
    }
    }
}
  

GetFileTimeSample 

{{1}}

答案 1 :(得分：0)

这是通过命令行执行文件操作的方法。不是最优雅的解决方案，但希望是一个有用的参考。

using System;
using System.IO;
using System.Diagnostics;

namespace StackOverflow_FileNameShenanigans
{
    class Program
    {
        static void Main(string[] args)
        {
            string contents;

            DateTime origAccessDate;
            DateTime origCreateDate;
            long sizeBytes;

            string path = @"\\?\C:\Test\BadFileName.";

            try
            {
                contents = CommandLineFileOps.ReadAllText(path);
                origAccessDate = CommandLineFileOps.LastAccessTime(path);
                origCreateDate = CommandLineFileOps.CreationTime(path);
                sizeBytes = CommandLineFileOps.Length(path);

                Console.WriteLine($"Contents: {contents}");
                Console.WriteLine($"OrigAccessDate: {origAccessDate}");
                Console.WriteLine($"OrigCreateDate: {origCreateDate}");
                Console.WriteLine($"SizeBytes: {sizeBytes}");
                Console.ReadKey();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                Console.ReadKey();
            }
        }

    }

    public static class CommandLineFileOps
    {
        public static string ReadAllText(string path)
        {
            string contents;
            RunOnCommandLine($"type {path}", out contents);

            contents = contents.Substring(0, contents.Length - 3);
            return contents;
        }

        public static DateTime CreationTime(string path)
        {
            string output;
            RunOnCommandLine($"dir /T:C {path}", out output);

            string dateLine = output.Split('\n')[5];
            string dateStr = dateLine.Replace("                 ", "\n").Split('\n')[0];
            return DateTime.Parse(dateStr);
        }

        public static DateTime LastAccessTime(string path)
        {
            string output;
            RunOnCommandLine($"dir /T:A {path}", out output);

            string dateLine = output.Split('\n')[5];
            string dateStr = dateLine.Replace("                 ", "\n").Split('\n')[0];
            return DateTime.Parse(dateStr);
        }

        public static long Length(string path)
        {
            string output;
            RunOnCommandLine($"dir {path}", out output);

            string lengthLine = output.Split('\n')[6];
            string lengthStr = lengthLine.Replace("              ", "\n").Split('\n')[2].Split(' ')[0];
            return long.Parse(lengthStr);
        }

        private static int RunOnCommandLine(string line)
        {
            Process cmd = new Process();
            cmd.StartInfo.FileName = "cmd.exe";
            cmd.StartInfo.RedirectStandardInput = true;
            cmd.StartInfo.RedirectStandardOutput = true;
            cmd.StartInfo.CreateNoWindow = true;
            cmd.StartInfo.UseShellExecute = false;
            cmd.Start();

            cmd.StandardInput.WriteLine(line);
            cmd.StandardInput.Flush();
            cmd.StandardInput.Close();
            cmd.WaitForExit();

            int exitCode = cmd.ExitCode;
            return exitCode;
        }

        private static int RunOnCommandLine(string line, out string output)
        {
            string tempPath = Path.GetTempFileName();
            int exitCode = RunOnCommandLine($"{line} > {tempPath}");
            output = File.ReadAllText(tempPath);
            File.Delete(tempPath);

            return exitCode;
        }
    }
}

答案 2 :(得分：0)

方法调用：

        string path = @"C:\Test\BadFileName.";

        DateTime createDate = cmdGetCreateDate(path);
        DateTime accessDate = cmdGetAccessDate(path);
        long bytes = cmdGetSizeBytes(path);

方法：

    private DateTime cmdGetCreateDate(string path)
    {
        DateTime createDate = new DateTime();
        int lastSlash = path.LastIndexOf(Convert.ToChar("\\"));
        string file = path.Substring(lastSlash + 1);
        string folder = path.Substring(0, lastSlash);

        string cmdexe = @"C:\Windows\System32\cmd.exe";
        string args = @"/c dir /T:C /A:-D """ + folder + "\"";

        Process procCreateDate = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = cmdexe,
                Arguments = args,
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            }
        };

        procCreateDate.Start();
        string output = procCreateDate.StandardOutput.ReadToEnd();

        if (!output.Contains(file))
        {
            return createDate; //File not found
        }

        string p = @"\b\d{2}/\d{2}/\d{4}\b\s+\d{2}:\d{2} ..";
        Regex rx = new Regex(p);
        Match m = rx.Match(output);

        if (m.Success)
        {
            DateTime.TryParse(m.Value, out createDate);
        }

        return createDate;
    }

private DateTime cmdGetAccessDate(string path)
    {
        DateTime accessDate = new DateTime();
        int lastSlash = path.LastIndexOf(Convert.ToChar("\\"));
        string file = path.Substring(lastSlash + 1);
        string folder = path.Substring(0, lastSlash);

        string cmdexe = @"C:\Windows\System32\cmd.exe";
        string args = @"/c dir /T:A /A:-D """ + folder + "\"";

        Process procCreateDate = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = cmdexe,
                Arguments = args,
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            }
        };

        procCreateDate.Start();
        string output = procCreateDate.StandardOutput.ReadToEnd();

        if (!output.Contains(file))
        {
            return accessDate; //File not found
        }

        string p = @"\b\d{2}/\d{2}/\d{4}\b\s+\d{2}:\d{2} ..";
        Regex rx = new Regex(p);
        Match m = rx.Match(output);

        if (m.Success)
        {
            DateTime.TryParse(m.Value, out accessDate);
        }

        return accessDate;
    }

    private long cmdGetSizeBytes(string path)
    {
        long bytes = -1;
        int lastSlash = path.LastIndexOf(Convert.ToChar("\\"));
        string file = path.Substring(lastSlash + 1);
        string folder = path.Substring(0, lastSlash);

        string cmdexe = @"C:\Windows\System32\cmd.exe";
        string args = @"/c dir /A:-D """ + folder + "\"";


        Process procCreateDate = new Process
        {
            StartInfo = new ProcessStartInfo
            {
                FileName = cmdexe,
                Arguments = args,
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            }
        };

        procCreateDate.Start();
        string output = procCreateDate.StandardOutput.ReadToEnd();

        if (!output.Contains(file))
        {
            return bytes; //File not found
        }

        string p = @"\d+ " + file;
        Regex rx = new Regex(p);
        Match m = rx.Match(output);

        if (m.Success)
        {
            string[] splitVal = m.Value.Split(Convert.ToChar(" "));
            bytes = Convert.ToInt64(splitVal[0]);
        }

        return bytes;
    }
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