How to programmatically set a file tag

Question

When using Windows Explorer to view files, I am given the opportunity to set the "tag", "category" or other attributes. For JPEG, a different set of attributes (including the "tag") are the parameters. I would like to be able to install them programmatically.

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

Answer 1

Tags in JPEG files are saved as IPTC keywords. There are several libraries available for reading and writing, if that is what you are asking for.

Explorer shows different columns for different file types because it knows that these file types support these additional columns. You can define shell plugins to support custom column information for your own file types. MSDN provides an overview.

Answer 2

I think that you want to get all the properties of the file that can be obtained by right-clicking in the explorer.

You can use this device:

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 successfully used it. It is working fine. To get the properties, you can do this:

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

respectfully

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Neftali

Answer 3

I do not know a standard way to store additional metadata information. Each application can register its own properties tab and can somehow store this metadata information.

I believe that you are talking about the function of image tags in a Windows photo album.

The information is stored in two files: pictures.pd4 and NavTree.state as defined by Gail Bjork, who wanted to delete this information .

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

Some people have defined a file format. But I did not find published specifications from anyone, from internal to Microsoft, or from external.

You also asked about other file attributes that can be set via

 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 has a logical result, which you can check to verify that the operation completed successfully.

Answer 4

I am developing a tag application right now and it seems like the best answer is the Windows Imaging Component API , which has implementations for reading and writing metadata for various image formats (Exif, IPTC, etc.). You should distinguish between file metadata in the file system and metadata inside the file itself - this is a link to the latter.

Getty Images also has a good WIC API programming article.