问题
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)?
回答1:
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.
回答2:
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
Neftalí
回答3:
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.
回答4:
I'm developing a tagging application right now, and it seems that the best answer is the Windows Imaging Component API, which has implementations for reading and writing metadata for various image formats (Exif, IPTC, etc.). A distinction should be made between metadata for the file in the filesystem and metadata within the file itself--this is referencing the latter.
Getty Images also has a good article on programming with the WIC API.
来源：https://stackoverflow.com/questions/3049652/how-do-i-programmatically-set-a-file-tag