VB Shell Programming

Adding Additional Formats

Since it sounds so easy to add support for bitmaps, let’s go ahead and do it. The first thing we want to do is add the bitmap format to the registry. The previous script already has the entry we need:

[HKEY_CLASSES_ROOT\CLSID\{5BE98B48-FD84-11D2-9FE5-00550076E06F}\DataFormats\GetSet\1]
@ = "2,1,16,3"

As stated earlier, these values correspond to <format, aspect, medium , direction >, in this case CF_BITMAP, DVASPEC

T_CONTENT, TYMED_GDI, and DATADIR_GET ORed with DATADIR_SET.

Next, we need to modify QueryGetData in order to recognize the new format. When the shell asks if we can provide bitmaps, we need to be able to tell it “yes.” Example 8.5 contains the modified version of the method.

Example 8-5. QueryGetData with Bitmap Format Added

Public Function QueryGetDataVB(ByVal this As IDataObject, _ 
                              pformatetc As FORMATETC) As Long

    QueryGetDataVB = DV_E_FORMATETC

    'Text
    If (pformatetc.cfFormat And CF_TEXT) And _
       (pformatetc.dwAspect = DVASPECT_CONTENT) And _
       (pformatetc.TYMED = TYMED_HGLOBAL) Then

        QueryGetDataVB = S_OK

    End If'Bitmap
    If (pformatetc.cfFormat And CF_BITMAP) And _
       (pformatetc.dwAspect = DVASPECT_CONTENT) And _
       (pformatetc.TYMED = TYMED_GDI) Then

        QueryGetDataVB = S_OK

    End If
    
End Function

Good news: we don’t have to do a thing with EnumFormatEtc. Everything there is already in place.

This leaves us with GetData. Since we are providing data in two formats now, it might be a good idea to clean up our implementation somewhat. We can move all of the ...