c# - 在 C# 中获取 unicode 目录名称？

Question

我正在尝试使用以下代码从我的 USB 驱动器中获取所有目录

DirectoryInfo di = new DirectoryInfo("H:\\");
DirectoryInfo[] allDir = di.GetDirectories();

此代码非常适用于具有 ascii 名称的目录。但是一个目录的名字是 ""(unicode 值 U+00A0)。 GetDirectories() 无法获取该目录。有没有办法获取带有 unicode 名称的目录？

Answer 1

好吧，所以你要解决的是 .NET 框架使用 FindFirstFile 的这个签名:

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true, BestFitMapping = false)]
internal static SafeFindHandle FindFirstFile(string fileName, [In, Out] Win32Native.WIN32_FIND_DATA data);

雪上加霜的是，你在与语言作斗争:

Automatically marshal strings appropriately for the target operating system. The default is Unicode on Windows NT, Windows 2000, Windows XP, and the Windows Server 2003 family; the default is Ansi on Windows 98 and Windows Me. Although the common language runtime default is Auto, languages may override this default. For example, by default C# marks all methods and types as Ansi.

(来自 CharSet 枚举文档强调添加)

手头的问题是 DllImport 上的 CharSet 参数。这意味着您只剩下一种方法；自己利用 P/Invoke。你需要很多东西。首先，您需要返回的数据结构:

[BestFitMapping(false)]
[Serializable]
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
internal class WIN32_FIND_DATA
{
  internal int dwFileAttributes;
  internal uint ftCreationTime_dwLowDateTime;
  internal uint ftCreationTime_dwHighDateTime;
  internal uint ftLastAccessTime_dwLowDateTime;
  internal uint ftLastAccessTime_dwHighDateTime;
  internal uint ftLastWriteTime_dwLowDateTime;
  internal uint ftLastWriteTime_dwHighDateTime;
  internal int nFileSizeHigh;
  internal int nFileSizeLow;
  internal int dwReserved0;
  internal int dwReserved1;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
  internal string cFileName;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
  internal string cAlternateFileName;

  [TargetedPatchingOptOut("Performance critical to inline this type of method across NGen image boundaries")]
  public WIN32_FIND_DATA()
  {
  }
}

接下来您需要为 FindFirstFile 正确导入:

[DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true, BestFitMapping = false)]
internal static SafeFindHandle FindFirstFile(string fileName, [In, Out] Win32Native.WIN32_FIND_DATA data);

接下来您需要GetLastWin32Error 来检查错误；可以通过 Marshal.GetLastWin32Error 访问在 InteropServices 命名空间中。

接下来您将需要迭代，因此您需要 FindNextFile:

[DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true, BestFitMapping = false)]
internal static bool FindNextFile(SafeFindHandle hndFindFile, [MarshalAs(UnmanagedType.LPStruct), In, Out] Win32Native.WIN32_FIND_DATA lpFindFileData);

有了这些，您就可以构建自己的迭代器。但是，为了您的利益，这里是 Microsoft 为“init”所做的事情:

[SecurityCritical]
private void CommonInit()
{
  string fileName = Path.InternalCombine(this.searchData.fullPath, this.searchCriteria);
  Win32Native.WIN32_FIND_DATA wiN32FindData = new Win32Native.WIN32_FIND_DATA();
  this._hnd = Win32Native.FindFirstFile(fileName, wiN32FindData);
  if (this._hnd.IsInvalid)
  {
    int lastWin32Error = Marshal.GetLastWin32Error();
    switch (lastWin32Error)
    {
      case 2:
      case 18:
        this.empty = this.searchData.searchOption == SearchOption.TopDirectoryOnly;
        break;
      default:
        this.HandleError(lastWin32Error, this.searchData.fullPath);
        break;
    }
  }
  if (this.searchData.searchOption == SearchOption.TopDirectoryOnly)
  {
    if (this.empty)
    {
      this._hnd.Dispose();
    }
    else
    {
      SearchResult searchResult = this.CreateSearchResult(this.searchData, wiN32FindData);
      if (!this._resultHandler.IsResultIncluded(searchResult))
        return;
      this.current = this._resultHandler.CreateObject(searchResult);
    }
  }
  else
  {
    this._hnd.Dispose();
    this.searchStack.Add(this.searchData);
  }
}

这是他们为“迭代”您正在寻找的内容所做的工作:

  if (this.searchData != null && this._hnd != null)
  {
    while (Win32Native.FindNextFile(this._hnd, wiN32FindData))
    {
      SearchResult searchResult = this.CreateSearchResult(this.searchData, wiN32FindData);
      if (this._resultHandler.IsResultIncluded(searchResult))
      {
        if (this.needsParentPathDiscoveryDemand)
        {
          this.DoDemand(this.searchData.fullPath);
          this.needsParentPathDiscoveryDemand = false;
        }
        this.current = this._resultHandler.CreateObject(searchResult);
        return true;
      }
    }
    int lastWin32Error = Marshal.GetLastWin32Error();
    if (this._hnd != null)
      this._hnd.Dispose();
    if (lastWin32Error != 0 && lastWin32Error != 18 && lastWin32Error != 2)
      this.HandleError(lastWin32Error, this.searchData.fullPath);
  }

注意:您将无法直接使用此代码，您必须将其应用到您的解决方案中，但这是 API 的一个巨大飞跃。给你一份 dotPeek填补空白。

注意 FindFirstFile 接受的fileName 参数将转到父目录。在您的情况下，H:\。