如何在Delphi中检查卷的8.3命名启用或禁用状态？

Absolutely, you can check whether 8.3 naming support is enabled for a specific volume in Delphi using Windows API functions. This is perfect for your use case where you need to alert users when long paths exceed the 260-character limit and 8.3 naming is disabled. Here's a complete, practical solution:

How to Check 8.3 Naming Status for a Volume #

The core approach uses the DeviceIoControl API with the FSCTL_GET_NTFS_VOLUME_DATA control code to fetch NTFS volume flags, including whether short-name creation is disabled. First, define the necessary Windows API types and constants in your Delphi project:

const
  FSCTL_GET_NTFS_VOLUME_DATA = $00090064;
  NTFS_VOLUME_FLAGS_SHORT_NAMES_DISABLED = $00000001;
  MAX_PATH = 260;

type
  LARGE_INTEGER = record
    case Integer of
      0: (LowPart: DWORD; HighPart: Longint);
      1: (QuadPart: Int64);
  end;

  NTFS_VOLUME_DATA_BUFFER = record
    VolumeSerialNumber: DWORD;
    NumberSectors: LARGE_INTEGER;
    TotalClusters: LARGE_INTEGER;
    FreeClusters: LARGE_INTEGER;
    TotalReserved: LARGE_INTEGER;
    BytesPerSector: DWORD;
    BytesPerCluster: DWORD;
    BytesPerFileRecordSegment: DWORD;
    ClustersPerFileRecordSegment: DWORD;
    MftValidDataLength: LARGE_INTEGER;
    MftStartLcn: LARGE_INTEGER;
    Mft2StartLcn: LARGE_INTEGER;
    MftZoneStart: LARGE_INTEGER;
    MftZoneEnd: LARGE_INTEGER;
    Flags: DWORD;
    // Omitted unused fields for brevity
  end;

Next, create a helper function to check the 8.3 status for a target volume:

function Is8dot3NamingDisabled(const VolumePath: string): Boolean;
var
  hVolume: THandle;
  VolumeData: NTFS_VOLUME_DATA_BUFFER;
  BytesReturned: DWORD;
begin
  Result := True; // Default to disabled if any error occurs

  // Open the volume using the extended path syntax (required for CreateFile)
  hVolume := CreateFile(PChar(VolumePath), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE,
    nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  if hVolume = INVALID_HANDLE_VALUE then
    Exit;

  try
    // Retrieve NTFS volume data via DeviceIoControl
    if DeviceIoControl(hVolume, FSCTL_GET_NTFS_VOLUME_DATA, nil, 0,
      @VolumeData, SizeOf(VolumeData), BytesReturned, nil) then
    begin
      // Check if the short-names-disabled flag is set
      Result := (VolumeData.Flags and NTFS_VOLUME_FLAGS_SHORT_NAMES_DISABLED) <> 0;
    end;
  finally
    CloseHandle(hVolume);
  end;
end;

Using the Check Function #

To check a specific drive (e.g., drive C:), call the function with the extended path format:

var
  IsDisabled: Boolean;
begin
  // Format: \\?\DriveLetter:\
  IsDisabled := Is8dot3NamingDisabled('\\?\C:\');
  if IsDisabled then
    ShowMessage('8.3 naming support is disabled on drive C:')
  else
    ShowMessage('8.3 naming support is enabled on drive C:');
end;

Integrating with Long Path Checks #

Combine this check with path-length validation to trigger your user prompt when needed:

function IsPathTooLong(const FilePath: string): Boolean;
begin
  // Check if the path exceeds the traditional 260-character limit
  Result := Length(FilePath) > MAX_PATH;
end;

procedure HandleLongPathScenario(const FilePath: string);
var
  VolumePath: string;
  Is8dot3Disabled: Boolean;
  DriveLetter: string;
begin
  if IsPathTooLong(FilePath) then
  begin
    // Extract the drive letter and format it for the volume check
    DriveLetter := ExtractFileDrive(FilePath);
    VolumePath := '\\?\' + IncludeTrailingPathDelimiter(DriveLetter);

    Is8dot3Disabled := Is8dot3NamingDisabled(VolumePath);
    if Is8dot3Disabled then
    begin
      if MessageDlg('The file path exceeds the maximum 260-character limit. 8.3 naming support is disabled on this drive, which could help shorten paths. Would you like to enable it?',
        mtConfirmation, [mbYes, mbNo], 0) = mrYes then
      begin
        // Prompt user to run the admin-only fsutil command
        ShowMessage('To enable 8.3 naming support:'#13#10 +
          '1. Open Command Prompt as Administrator'#13#10 +
          '2. Run this command:'#13#10 +
          '   fsutil file setdisable8dot3 ' + DriveLetter + ' 0'#13#10#13#10 +
          'You may need to restart your system for changes to take effect.');
      end;
    end;
  end;
end;

Key Notes #

• NTFS Only: This check works exclusively for NTFS volumes. FAT32 volumes always support 8.3 naming by default.
• Admin Rights: Enabling 8.3 naming requires administrative privileges, so make sure to highlight this in your prompt.
• Existing Files: Enabling 8.3 naming won't retroactively generate short names for existing files—it only applies to new files created after the change.

内容的提问来源于stack exchange，提问作者Serraniel