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172

answers:

3

When using Windows Explorer to view files, I'm given the option to set a "tag", "category", or other attributes. For a JPEG a different set of attributes (including "tag") are options. I'd like to be able to set these programmatically.

How do I programmatically set a file tag and other file attributes using Delphi (I have Delphi 2010 Pro)?

+2  A: 

I know of no standard way to store additional meta data information. Each application can register there own property tab and could store this meta data information in any way.

I believe your talking about the image tagging feature of Windows Photo Gallery.

The information is stored in two files: pictures.pd4 and NavTree.state as determined by Gail Bjork person who wanted to remove this information.

This stored in: C:\Users\YourUser\AppData\Local\Microsoft\Windows Photo Gallery.

Some people have figured out the file format. But I have not found a published spec from anyone internal to Microsoft or external.

You also asked about other file attributes these can be set through the

FileSetAttr(FileName,Attribute)

Attributes that can be set:

  • faReadOnly
  • faHidden
  • faSysFile
  • faVolumeID
  • faDirectory
  • faArchive
  • faSymLink

//The following sets test.txt to a readonly and hidden file. FileSetAttr('C:\Test.txt',faReadOnly or faHidden);

The function does have a boolean result that you can check to see if the operation completed successfully.

Robert Love
It sounds as though my initial assumption was wrong, that all files can have a tag assigned. You're right, I'm using Windows Live with the Photo Gallery; I didn't realize some of the tagging feature were installed with it.Thank you for the help.
Greg Bishop
+5  A: 

Tags in JPEG files are stored as IPTC keywords. There are a few libraries available for reading and writing those, if that's what you're asking for.

Explorer shows different columns for different file types because it knows that those file types support those extra columns. You can define shell plug-ins to support custom column information for your own file types. MSDN provides an overview.

Rob Kennedy
+1 for the MSDN link.
François
As per my comment to Robert, I had the misconception that I could assign tags to ALL files, not just my own format. I thought it would be a nice way to facilitate the creation of a poor-man's disk-based document management system by linking any file to a project or contact by using a tag in the file to store the ProjectID or ContactID.It sounds like I may be out-of-luck if this can only be done for file formats that have had the desired attributes defined for them (or for my own file formats).Thank you for your help.
Greg Bishop
Nope, we're not quite there yet. There are the beginnings of a [tag-based filesystem](http://code.google.com/p/xtagfs/) for Macintosh that works by manipulating symbolic links. Microsoft was working on a [database-based filesystem](http://en.wikipedia.org/wiki/WinFS) many years ago that could probably work with tags pretty well, but it seems like that project has been largely stagnate for the past several years; it was supposed to be in Vista.
Rob Kennedy
+1  A: 

I think that you want retrieve all properties of the file that can be accesed pressing right button on mouse in explorer.

You can use this unit:

unit u_fsummary;

interface

uses Windows, ComObj, ActiveX, Variants, Sysutils;

procedure SetFileSummaryInfo(const FileName : WideString; Author, Title, Subject, Keywords, Comments : WideString);
function GetFileSummaryInfo(const FileName: WideString): String;
function IsNTFS(AFileName : string) : boolean;

implementation

const

FmtID_SummaryInformation: TGUID =     '{F29F85E0-4FF9-1068-AB91-08002B27B3D9}';
FMTID_DocSummaryInformation : TGUID = '{D5CDD502-2E9C-101B-9397-08002B2CF9AE}';
FMTID_UserDefinedProperties : TGUID = '{D5CDD505-2E9C-101B-9397-08002B2CF9AE}';
IID_IPropertySetStorage : TGUID =     '{0000013A-0000-0000-C000-000000000046}';

STGFMT_FILE = 3; //Indicates that the file must not be a compound file.
                 //This element is only valid when using the StgCreateStorageEx
                 //or StgOpenStorageEx functions to access the NTFS file system
                 //implementation of the IPropertySetStorage interface.
                 //Therefore, these functions return an error if the riid
                 //parameter does not specify the IPropertySetStorage interface,
                 //or if the specified file is not located on an NTFS file system volume.

STGFMT_ANY = 4; //Indicates that the system will determine the file type and
                //use the appropriate structured storage or property set
                //implementation.
                //This value cannot be used with the StgCreateStorageEx function.


// Summary Information
 PID_TITLE        = 2;
 PID_SUBJECT      = 3;
 PID_AUTHOR       = 4;
 PID_KEYWORDS     = 5;
 PID_COMMENTS     = 6;
 PID_TEMPLATE     = 7;
 PID_LASTAUTHOR   = 8;
 PID_REVNUMBER    = 9;
 PID_EDITTIME     = 10;
 PID_LASTPRINTED  = 11;
 PID_CREATE_DTM   = 12;
 PID_LASTSAVE_DTM = 13;
 PID_PAGECOUNT    = 14;
 PID_WORDCOUNT    = 15;
 PID_CHARCOUNT    = 16;
 PID_THUMBNAIL    = 17;
 PID_APPNAME      = 18;
 PID_SECURITY     = 19;

 // Document Summary Information
 PID_CATEGORY     = 2;
 PID_PRESFORMAT   = 3;
 PID_BYTECOUNT    = 4;
 PID_LINECOUNT    = 5;
 PID_PARCOUNT     = 6;
 PID_SLIDECOUNT   = 7;
 PID_NOTECOUNT    = 8;
 PID_HIDDENCOUNT  = 9;
 PID_MMCLIPCOUNT  = 10;
 PID_SCALE        = 11;
 PID_HEADINGPAIR  = 12;
 PID_DOCPARTS     = 13;
 PID_MANAGER      = 14;
 PID_COMPANY      = 15;
 PID_LINKSDIRTY   = 16;
 PID_CHARCOUNT2   = 17;

function IsNTFS(AFileName : string) : boolean;
var
fso, drv : OleVariant;
begin
IsNTFS := False;
fso := CreateOleObject('Scripting.FileSystemObject');
drv := fso.GetDrive(fso.GetDriveName(AFileName));
 if drv.FileSystem = 'NTFS' then
  IsNTFS := True;
end;

function StgOpenStorageEx (
 const pwcsName : POleStr;  //Pointer to the path of the
                            //file containing storage object
 grfMode : LongInt;         //Specifies the access mode for the object
 stgfmt : DWORD;            //Specifies the storage file format
 grfAttrs : DWORD;          //Reserved; must be zero
 pStgOptions : Pointer;     //Address of STGOPTIONS pointer
 reserved2 : Pointer;       //Reserved; must be zero
 riid : PGUID;              //Specifies the GUID of the interface pointer
 out stgOpen :              //Address of an interface pointer
 IStorage ) : HResult; stdcall; external 'ole32.dll';


function GetFileSummaryInfo(const FileName: WideString): String;

var
 I: Integer;
 PropSetStg: IPropertySetStorage;
 PropSpec: array of TPropSpec;
 PropStg: IPropertyStorage;
 PropVariant: array of TPropVariant;
 Rslt: HResult;
 S: String;
 Stg: IStorage;
 PropEnum: IEnumSTATPROPSTG;
 HR : HResult;
 PropStat: STATPROPSTG;
 k : integer;

function PropertyPIDToCaption(const ePID: Cardinal): string;
begin
 case ePID of
   PID_TITLE:
     Result := 'Title';
   PID_SUBJECT:
     Result := 'Subject';
   PID_AUTHOR:
     Result := 'Author';
   PID_KEYWORDS:
     Result := 'Keywords';
   PID_COMMENTS:
     Result := 'Comments';
   PID_TEMPLATE:
     Result := 'Template';
   PID_LASTAUTHOR:
     Result := 'Last Saved By';
   PID_REVNUMBER:
     Result := 'Revision Number';
   PID_EDITTIME:
     Result := 'Total Editing Time';
   PID_LASTPRINTED:
     Result := 'Last Printed';
   PID_CREATE_DTM:
     Result := 'Create Time/Date';
   PID_LASTSAVE_DTM:
     Result := 'Last Saved Time/Date';
   PID_PAGECOUNT:
     Result := 'Number of Pages';
   PID_WORDCOUNT:
     Result := 'Number of Words';
   PID_CHARCOUNT:
     Result := 'Number of Characters';
   PID_THUMBNAIL:
     Result := 'Thumbnail';
   PID_APPNAME:
     Result := 'Creating Application';
   PID_SECURITY:
     Result := 'Security';
   else
     Result := '$' + IntToHex(ePID, 8);
   end
end;

begin
 Result := '';
try
 OleCheck(StgOpenStorageEx(PWideChar(FileName),
 STGM_READ or STGM_SHARE_DENY_WRITE,
 STGFMT_FILE,
 0, nil,  nil, @IID_IPropertySetStorage, stg));

 PropSetStg := Stg as IPropertySetStorage;

 OleCheck(PropSetStg.Open(FmtID_SummaryInformation,
    STGM_READ or STGM_SHARE_EXCLUSIVE, PropStg));

 OleCheck(PropStg.Enum(PropEnum));
 I := 0;

 hr := PropEnum.Next(1, PropStat, nil);
  while hr = S_OK do
  begin
    inc(I);
    SetLength(PropSpec,I);
    PropSpec[i-1].ulKind := PRSPEC_PROPID;
    PropSpec[i-1].propid := PropStat.propid;
    hr := PropEnum.Next(1, PropStat, nil);
 end;

 SetLength(PropVariant,i);
 Rslt := PropStg.ReadMultiple(i, @PropSpec[0], @PropVariant[0]);

 if Rslt =  S_FALSE then Exit;

 for k := 0 to i -1 do
  begin
    S := '';
    if PropVariant[k].vt = VT_LPSTR then
      if Assigned(PropVariant[k].pszVal) then
       S := PropVariant[k].pszVal;

    S := Format(PropertyPIDToCaption(PropSpec[k].Propid)+ ' %s',[s]);
   if S <> '' then Result := Result + S + #13;
 end;
 finally
 end;
end;

procedure SetFileSummaryInfo(const FileName : WideString; Author, Title, Subject, Keywords, Comments : WideString);

var
PropSetStg: IPropertySetStorage;
PropSpec: array of TPropSpec;
PropStg: IPropertyStorage;
PropVariant: array of TPropVariant;
Stg: IStorage;

begin
 OleCheck(StgOpenStorageEx(PWideChar(FileName), STGM_SHARE_EXCLUSIVE or STGM_READWRITE, STGFMT_ANY, 0, nil,  nil, @IID_IPropertySetStorage, stg));
 PropSetStg := Stg as IPropertySetStorage;
 OleCheck(PropSetStg.Create(FmtID_SummaryInformation, FmtID_SummaryInformation, PROPSETFLAG_DEFAULT,STGM_CREATE or STGM_READWRITE or STGM_SHARE_EXCLUSIVE, PropStg));
 Setlength(PropSpec,6);
 PropSpec[0].ulKind := PRSPEC_PROPID;
 PropSpec[0].propid := PID_AUTHOR;
 PropSpec[1].ulKind := PRSPEC_PROPID;
 PropSpec[1].propid := PID_TITLE;
 PropSpec[2].ulKind := PRSPEC_PROPID;
 PropSpec[2].propid := PID_SUBJECT;
 PropSpec[3].ulKind := PRSPEC_PROPID;
 PropSpec[3].propid := PID_KEYWORDS;
 PropSpec[4].ulKind := PRSPEC_PROPID;
 PropSpec[4].propid := PID_COMMENTS;
 PropSpec[5].ulKind := PRSPEC_PROPID;
 PropSpec[5].propid := 99;

 SetLength(PropVariant,6);
 PropVariant[0].vt:=VT_LPWSTR;
 PropVariant[0].pwszVal:=PWideChar(Author);
 PropVariant[1].vt:=VT_LPWSTR;
 PropVariant[1].pwszVal:=PWideChar(Title);
 PropVariant[2].vt:= VT_LPWSTR;
 PropVariant[2].pwszVal:=PWideChar(Subject);
 PropVariant[3].vt:= VT_LPWSTR;
 PropVariant[3].pwszVal:=PWideChar(Keywords);
 PropVariant[4].vt:= VT_LPWSTR;
 PropVariant[4].pwszVal:=PWideChar(Comments);
 PropVariant[5].vt:= VT_LPWSTR;
 PropVariant[5].pwszVal:=PWideChar(Comments);
 OleCheck(PropStg.WriteMultiple(6, @PropSpec[0], @PropVariant[0], 2 ));
 PropStg.Commit(STGC_DEFAULT);
end;


end.

This is not my code, but i have used it successfully. It work fine. To retrieve properties you can do this:

mmProps2.Lines.Text := GetFileSummaryInfo(edtFile.Text);

Regards


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Neftalí