Author: Bertrand Goetzmann

How read or write in the summary information of an Offiche document ?

Answer:

An Office document file is a structured storage file that an application can read 
with the StgOpenStorage function from the Windows API. This kind of file is made of 
storages and streams. 
COM defines a standard common property set for storing summary information about 
document. This information is stored in a stream under the root storage. The 
following function shows how you can get the author property by giving a filename : 

1   uses ActiveX, ComObj, SysUtils;
2   
3   function GetSummaryInfAuthor(FileName: TFileName): string;
4   var
5     PFileName: PWideChar;
6     Storage: IStorage;
7     PropSetStg: IPropertySetStorage;
8     PropStg: IPropertyStorage;
9     ps: PROPSPEC;
10    pv: PROPVARIANT;
11  const
12    FMTID_SummaryInformation: TGUID = '{F29F85E0-4FF9-1068-AB91-08002B27B3D9}';
13  begin
14    PFileName := StringToOleStr(FileName);
15    try
16      // Open compound storage
17      OleCheck(StgOpenStorage(PFileName, nil, STGM_DIRECT or STGM_READ or
18        STGM_SHARE_EXCLUSIVE, nil, 0, Storage));
19    finally
20      SysFreeString(PFileName);
21    end;
22  
23    // Summary information is in a stream under the root storage
24    PropSetStg := Storage as IPropertySetStorage;
25    // Get the IPropertyStorage
26    OleCheck(PropSetStg.Open(FMTID_SummaryInformation, STGM_DIRECT or STGM_READ or
27      STGM_SHARE_EXCLUSIVE, PropStg));
28  
29    // We want the author property value
30    ps.ulKind := PRSPEC_PROPID;
31    ps.propid := PIDSI_AUTHOR;
32  
33    // Read this property
34    PropStg.ReadMultiple(1, @ps, @pv);
35  
36    Result := pv.pszVal;
37  end;


See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/com/stgasstg_7agk.asphttp://msdn.microsoft.com/library/default.asp?url=/library/en-us/com/stgasstg_7agk.asp for more information about the Summary Information Property Set.