HOWTO: Read Compound Document Properties Directly with VC++

• Microsoft Visual C++, 32-bit Editions, version 5.0
• Microsoft Office 97 for Windows

SUMMARY

You can retrieve compound document properties from a document using standard interfaces without the server running or even being installed. For instance, you can retrieve built-in document properties such as Author, Last Modified Time, and Page Count properties of a Microsoft Office 97 document as well as other custom document properties.

MORE INFORMATION

The following steps illustrate how you can build a compound document property viewer with Microsoft Visual C++. The example is a Win32 Console Application project, and can be modified to suit your needs.

Steps to Create Sample

1. Create a new Win32 Console Application project, and call it PropDump.



2. Add a new file called main.cpp to your project.



3. Copy the following code into main.cpp:




   #include <stdio.h>
   #include <windows.h>
   #include <ole2.h>


   // Dumps simple PROPVARIANT values.
   void DumpPropVariant(PROPVARIANT *pPropVar) {
      // Don't iterate arrays, just inform as an array.
      if(pPropVar->vt & VT_ARRAY) {
         printf("(Array)\n");
         return;
      }
      // Don't handle byref for simplicity, just inform byref.
      if(pPropVar->vt & VT_BYREF) {
         printf("(ByRef)\n");
         return;
       }

      // Switch types.
      switch(pPropVar->vt) {
      case VT_EMPTY:
         printf("(VT_EMPTY)\n");
         break;
      case VT_NULL:
         printf("(VT_NULL)\n");
         break;
      case VT_BLOB:
         printf("(VT_BLOB)\n");
         break;
      case VT_BOOL:
         printf("%s (VT_BOOL)\n",
         pPropVar->boolVal ? "TRUE/YES" : "FALSE/NO");
         break;
      case VT_I2: // 2-byte signed int.
         printf("%d (VT_I2)\n", (int)pPropVar->iVal);
         break;
      case VT_I4: // 4-byte signed int.
         printf("%d (VT_I4)\n", (int)pPropVar->lVal);
         break;
      case VT_R4: // 4-byte real.
         printf("%.2lf (VT_R4)\n", (double)pPropVar->fltVal);
         break;
      case VT_R8: // 8-byte real.
         printf("%.2lf (VT_R8)\n", (double)pPropVar->dblVal);
         break;
         case VT_BSTR: // OLE Automation string.
         {
            // Translate into ASCII.
            char dbcs[1024];
            char *pbstr = (char *)pPropVar->bstrVal;
            int i = wcstombs(
            dbcs, pPropVar->bstrVal, *((DWORD *)(pbstr-4)));
            dbcs[i] = 0;
            printf("%s (VT_BSTR)\n", dbcs);
         }
         break;
      case VT_LPSTR: // Null-terminated string.
         {
         printf("%s (VT_LPSTR)\n", pPropVar->pszVal);
         }
         break;
      case VT_FILETIME:
         {
            char *dayPre[] =
                         {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};

            FILETIME lft;
            FileTimeToLocalFileTime(&pPropVar->filetime, &lft);                SYSTEMTIME lst;
            FileTimeToSystemTime(&lft, &lst);

            printf("%02d:%02d.%02d %s, %s %02d/%02d/%d (VT_FILETIME)\n",
               1+(lst.wHour-1)%12, lst.wMinute, lst.wSecond,
               (lst.wHour>=12) ? "pm" : "am",
               dayPre[lst.wDayOfWeek%7],
               lst.wMonth, lst.wDay, lst.wYear);
         }
         break;
      case VT_CF: // Clipboard format.
         printf("(Clipboard format)\n");

         break;
      default: // Unhandled type, consult wtypes.h's VARENUM structure.
         printf("(Unhandled type: 0x%08lx)\n", pPropVar->vt);
         break;
      }
   }

   // Dump's built-in properties of a property storage.
   void DumpBuiltInProps(IPropertySetStorage *pPropSetStg) {
      printf("\n==================================================\n");
      printf("BuiltInProperties Properties...\n");
      printf("==================================================\n");

      IPropertyStorage *pPropStg = NULL;
      HRESULT hr;

      // Open summary information, getting an IpropertyStorage.
      hr = pPropSetStg->Open(FMTID_SummaryInformation,
      STGM_READ | STGM_SHARE_EXCLUSIVE, &pPropStg);
      //hr = pPropSetStg->Open(FMTID_UserDefinedProperties,
         //STGM_READ | STGM_SHARE_EXCLUSIVE, &pPropStg);
      if(FAILED(hr)) {
         printf("No Summary-Information.\n");
         return;
      }
      // Array of PIDSI's you are interested in.
      struct pidsiStruct {
         char *name;
         long pidsi;
      } pidsiArr[] = {
         {"Title",            PIDSI_TITLE}, // VT_LPSTR
         {"Subject",          PIDSI_SUBJECT}, // ...
         {"Author",           PIDSI_AUTHOR},
         {"Keywords",         PIDSI_KEYWORDS},
         {"Comments",         PIDSI_COMMENTS},
         {"Template",         PIDSI_TEMPLATE},
         {"LastAuthor",       PIDSI_LASTAUTHOR},
         {"Revision Number",  PIDSI_REVNUMBER},
         {"Edit Time",        PIDSI_EDITTIME}, // VT_FILENAME (UTC)
         {"Last printed",     PIDSI_LASTPRINTED}, // ...
         {"Created",          PIDSI_CREATE_DTM},
         {"Last Saved",       PIDSI_LASTSAVE_DTM},
         {"Page Count",       PIDSI_PAGECOUNT}, // VT_I4
         {"Word Count",       PIDSI_WORDCOUNT}, // ...
         {"Char Count",       PIDSI_CHARCOUNT},
         {"Thumpnail",        PIDSI_THUMBNAIL}, // VT_CF
         {"AppName",          PIDSI_APPNAME}, // VT_LPSTR
         {"Doc Security",     PIDSI_DOC_SECURITY}, // VT_I4
         {0, 0}
      };
      // Count elements in pidsiArr.
      int nPidsi = 0;
      for(nPidsi=0; pidsiArr[nPidsi].name; nPidsi++);

      // Initialize PROPSPEC for the properties you want.
      PROPSPEC *pPropSpec = new PROPSPEC [nPidsi];
      PROPVARIANT *pPropVar = new PROPVARIANT [nPidsi];

      for(int i=0; i<nPidsi; i++) {
         ZeroMemory(&pPropSpec[i], sizeof(PROPSPEC));
         pPropSpec[i].ulKind = PRSPEC_PROPID;
         pPropSpec[i].propid = pidsiArr[i].pidsi;
      }

      // Read properties.
      hr = pPropStg->ReadMultiple(nPidsi, pPropSpec, pPropVar);

      if(FAILED(hr)) {
         printf("IPropertyStg::ReadMultiple() failed w/error %08lx\n",
                hr);
      }
      else {
         // Dump properties.
         for(i=0; i<nPidsi; i++) {
            printf("%16s: ", pidsiArr[i].name);
            DumpPropVariant(pPropVar + i);
         }
      }

      // De-allocate memory.
      delete [] pPropVar;
      delete [] pPropSpec;

      // Release obtained interface.
      pPropStg->Release();

   }

   // Dump's custom properties of a property storage.
   void DumpCustomProps(IPropertySetStorage *pPropSetStg) {
      printf("\n==================================================\n");
      printf("Custom Properties...\n");
      printf("==================================================\n");

      IPropertyStorage *pPropStg = NULL;
      HRESULT hr;
      IEnumSTATPROPSTG *pEnumProp;

      // Open User-Defined-Properties, getting an IpropertyStorage.
      hr = pPropSetStg->Open(FMTID_UserDefinedProperties,
         STGM_READ | STGM_SHARE_EXCLUSIVE, &pPropStg);
      if(FAILED(hr)) {
         printf("No User Defined Properties.\n");
         return;
      }

      // Get property enumerator.
      hr = pPropStg->Enum(&pEnumProp);
      if(FAILED(hr)) {
      pPropStg->Release();
         printf("Couldn't enumerate custom properties.\n");
         return;
      }

      // Enumerate properties.
      STATPROPSTG sps;
      ULONG fetched;
      PROPSPEC propSpec[1];
      PROPVARIANT propVar[1];
      while(pEnumProp->Next(1, &sps, &fetched) == S_OK) {
         // Build a PROPSPEC for this property.
         ZeroMemory(&propSpec[0], sizeof(PROPSPEC));
         propSpec[0].ulKind = PRSPEC_PROPID;
         propSpec[0].propid = sps.propid;

         // Read this property.
         hr = pPropStg->ReadMultiple(1, &propSpec[0], &propVar[0]);
         if(!FAILED(hr)) {
            // Translate Prop name into ASCII.
            char dbcs[1024];
            char *pbstr = (char *)sps.lpwstrName;
            int i = wcstombs(dbcs, sps.lpwstrName,
                             *((DWORD *)(pbstr-4)));
            dbcs[i] = 0;

            // Dump this property.
            printf("%16s: ", dbcs);
            DumpPropVariant(&propVar[0]);
         }
      }

      // Release obtained interface.
      pEnumProp->Release();
      pPropStg->Release();

   }

   // Dump's custom and built-in properties of a compound document.
   void DumpProps(char *filename) {
      // Translate filename to Unicode.
      WCHAR wcFilename[1024];
      int i = mbstowcs(wcFilename, filename, strlen(filename));
      wcFilename[i] = 0;

      IStorage *pStorage = NULL;
      IPropertySetStorage *pPropSetStg = NULL;
      HRESULT hr;

      // Open the document as an OLE compound document.
      hr = ::StgOpenStorage(wcFilename, NULL,
      STGM_READ | STGM_SHARE_EXCLUSIVE, NULL, 0, &pStorage);

      if(FAILED(hr)) {
         if(hr == STG_E_FILENOTFOUND)
            printf("File not found.");
         else if(hr == STG_E_FILEALREADYEXISTS)
            printf("Not a compound file.");
         else
            printf("StgOpenStorage() failed w/error %08lx", hr);
         return;
      }

      // Obtain the IPropertySetStorage interface.
      hr = pStorage->QueryInterface(
              IID_IPropertySetStorage, (void **)&pPropSetStg);
      if(FAILED(hr)) {
         printf("QI for IPropertySetStorage failed w/error %08lx", hr);
         pStorage->Release();
         return;
      }

      // Dump properties.
      DumpBuiltInProps(pPropSetStg);
      DumpCustomProps(pPropSetStg);

      // Release obtained interfaces.
      pPropSetStg->Release();
      pStorage->Release();
   }

      // Program entry-point.
      void main(int argc, char **argv) {
         // Validate arguments.
         if(argc != 2) {
            printf("- OLE Document Property Viewer\n");
            printf("- Usage: %s filename", argv[0]);
            return;
         }

         // Pass filename to the subroutine.
         DumpProps(argv[1]);
      }
   } 

4. Compile the program.

BuiltInProperties Properties...

           Title: MyTitle (VT_LPSTR)
         Subject: MySubject (VT_LPSTR)
          Author: MyAuthor (VT_LPSTR)
        Keywords: MyKeywords (VT_LPSTR)
        Comments: MyComments (VT_LPSTR)
        Template: Normal (VT_LPSTR)
      LastAuthor: Me (VT_LPSTR)

 Revision Number: 8 (VT_LPSTR)

       Edit Time: 01:05.47 pm, Mon 01/01/1601 (VT_FILETIME)
    Last printed: (VT_EMPTY)
         Created: 01:42.00 pm, Fri 05/29/1998 (VT_FILETIME)
      Last Saved: 12:31.00 pm, Mon 06/01/1998 (VT_FILETIME)
      Page Count: 1 (VT_I4)
      Word Count: 3 (VT_I4)
      Char Count: 19 (VT_I4)
       Thumpnail: (VT_EMPTY)
         AppName: Microsoft Word 8.0 (VT_LPSTR)
    Doc Security: 0 (VT_I4) 

Custom Properties...

   _PID_LINKBASE: (VT_BLOB)

       _PID_GUID: (VT_BLOB)
       CustProp1: CustProp1TextValue (VT_LPSTR)
       CustProp2: 77777 (VT_I4)
       CustProp3: TRUE/YES (VT_BOOL)
       CustProp4: 00:00.00 am, Tue 05/17/1977 (VT_FILETIME) 

Additional Notes

• Windows NT 4.0 or later
• Windows 95 with Internet Explorer version 4.0 or later
• Windows 95 with DCOM installed

REFERENCES

Microsoft Developer Network: Persistent Property Sets

Microsoft Developer Network: OLE Serialized Property Set Format

Additional query words: Excel Word Access Powerpoint Binder documentproperties builtindocumentproperties customdocumentproperties

Keywords : kbcode kbCmpDoc kbCOMt kbVC kbVC500 kbfaq kbDSupport kbOffice
Version : WINDOWS:97; winnt:5.0
Platform : WINDOWS winnt
Issue type : kbhowto