Microsoft KB Archive/114600

= FORMATETC for IDataObject: DAdvise Must be Validated =

Article ID: 114600

Article Last Modified on 3/3/2005

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APPLIES TO

 Microsoft OLE 2.01 Microsoft OLE 4.0, when used with:  Microsoft Windows NT 4.0

 Microsoft Windows NT 3.51 Service Pack 5

 Microsoft Windows NT 4.0

 Microsoft Windows 95</li></ul>

 Microsoft Windows 2000 Standard Edition</li></ul> </li></ul>

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This article was previously published under Q114600

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SUMMARY
Applications implementing IDataObject must validate the FORMATETC structure that is passed to IDataObject::DAdvise. Some commercial applications, such as Microsoft Excel 5.0, will try to set up an Advise on their own native format before setting up an Advise on the format selected by the user in the Paste Special dialog box while creating a link.

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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".

Additional query words: 2.01 3.50 4.00

Keywords: kbprogramming KB114600

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