FORMATETC for IDataObject: DAdvise Must be Validated

MORE INFORMATION

When validating the FORMATETC structure, the server application needs to allow wildcard Advises to succeed. A Wildcard Advise is an Advise set up by the default link object so that it can properly maintain the time-of-last- change. A Wildcard Advise is requested by passing a FORMATETC with cfFormat = 0, ptd = NULL, dwAspect = -1L, and tymed = -1L. Code to validate the FORMATETC structure might look as follows:

   // if not a Wildcard Advise and the data format is not supported,
   // return failure.

   if( !(pfmtetc->cfFormat == NULL  &&
         pfmtetc->ptd      == NULL  &&
         pfmtetc->dwAspect == -1L   &&
         pfmtetc->lindex   == -1L   &&
         pfmtetc->tymed    == -1L)
      && FAILED(hres = QueryGetData(pfmtetc)) )
      return hres;

   // Now pass on to the Data Advise holder
				

For more information on the IDataObject::DAdvise() member function, please refer to pages 436-439 of the "OLE Programmer's Reference, Volume 1".