Custom File Properties in Win 7

In previous code for Win Xp etc I set some custom file properties as in the code below. I now find in Win7 that this locks my file because the pPropSetStg->Release() fails. But further, on Win 7 there are no custom file properties? Or at least they don't work in the same way. I can't find anything about why this was changed or how to get around it. Does anyone know (or have a link to) the proper Win7 way to do this?


EDIT:

A partial answer... to make the built in custom properties appear for your file type, you neeed to add a registry key as per System Supplied Property Handlers[^].

I added the registry entry to display the four properties I'm after, however, the code below still doesn't work (it won't release, and doesn't set the specified properties).

If I try then to edit the properties manually in Windows Explorer, I get..

"An unexpected error is keeping you from applying properties to the file...

Error 0x80004005: Unspecified Error"

USES_CONVERSION;
WCHAR wcFilename[1024];
IStorage *pStorage = NULL;
IPropertyStorage *pPropStg = NULL;
IPropertySetStorage *pPropSetStg = NULL;
PROPSPEC propspec[4];
PROPVARIANT propvarWrite[4];
HRESULT hr;
IID riid;

const FMTID fmtid = FMTID_SummaryInformation;
const int MAX_BIG_STRING_LEN = 1024;

setlocale(LC_ALL, "");
size_t i = mbstowcs(wcFilename, newName, strlen(newName));
setlocale(LC_ALL, "C");
wcFilename[i] = 0;

riid = IID_IPropertySetStorage;

hr = StgOpenStorageEx(wcFilename, STGM_READ|STGM_SHARE_DENY_WRITE, STGFMT_FILE, 0, NULL, NULL, riid, (void **)(&pStorage));
if (!FAILED(hr) && pStorage != NULL)
{
    hr = pStorage->QueryInterface(riid, (void **)&pPropSetStg);
    if (!FAILED(hr) && pPropSetStg != NULL)
    {
        hr = pPropSetStg->Create(fmtid, NULL, PROPSETFLAG_DEFAULT, STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE, &pPropStg);

        if (!FAILED(hr) && pPropStg != NULL)
        {
            propspec[0].ulKind = PRSPEC_PROPID;
            propspec[0].propid = PIDSI_TITLE;
            propvarWrite[0].vt = VT_LPWSTR;
            propvarWrite[0].pwszVal = A2W(MyTitle);

            propspec[1].ulKind = PRSPEC_PROPID;
            propspec[1].propid = PIDSI_SUBJECT;
            propvarWrite[1].vt = VT_LPWSTR;
            propvarWrite[1].pwszVal = A2W(MyDescription);

            propspec[2].ulKind = PRSPEC_PROPID;
            propspec[2].propid = PIDSI_AUTHOR;
            propvarWrite[2].vt = VT_LPWSTR;
            propvarWrite[2].pwszVal = A2W(MyAuthor);

            propspec[3].ulKind = PRSPEC_PROPID;
            propspec[3].propid = PIDSI_COMMENTS;
            propvarWrite[3].vt = VT_LPWSTR;
            propvarWrite[3].pwszVal = A2W(MyComments);

            hr = pPropStg->WriteMultiple(4, propspec, propvarWrite, NULL);
            if (!FAILED(hr))
            {
                hr = pPropStg->Commit(STGC_DEFAULT);
            }

            hr = pPropStg->Release();
            pPropStg = NULL;
        }

        hr = pPropSetStg->Release();
        pPropSetStg = NULL;
    }
}

Tags: Windows, Windows 7, File