Export chart to stream - PLEASE HELP

[User (Legacy)]

Frank, 

I have been trying unsuccessfully to export a chart to a stream (I'm using 

Delphi 5). I found the newsgroup message that has a C example of how to do 

this: 

variant v; 

v_vt(&v) = VT_STREAM; 

V_UNKNOWN(&v) = pStream (points to a valid IStream). 

I have ported this code to Delphi, and I receive the ole error "invalid 

variant operation". 

After some research, I found in the Win32 Developer's Help reference that a 

VT_STREAM is not a valid type indicator for a variant (see below): 

******* From the Win32 Developer's Help for "Type Indicators" 

******************* 

The following table lists the standard OLE-defined property type indicators 

and their meaning: 

VT_STREAM 66 A VT_LPSTR (DWORD count of bytes followed by a zero-terminated 

string that many bytes long) that names the stream containing the data. The 

real value for this property is stored in a stream object, which is a 

sibling to the Contents stream. This type is only valid for property sets 

stored in the Contents stream of a storage object. 

********************************************************************* 

Is there another type indicator that the Export method may accept? I have 

tried using VT_UNKNOWN, and I don't get the ole error, but the export fails 

(returns a very long negative number: -2187......). How is the export 

working in ANY language if the Help statement is true? 

Here is the Delphi port code, any help is greatly appreciated. I have tried 

many different variations of this code (using variant, Olevariant, casting 

the streamadapter as IUnKnown, etc.): 

procedure TForm1.btnExportClick(Sender: TObject); 

var 

    vData: oleVariant; 

    tmpReturn : OleVariant; 

    AStream :  TStreamAdapter; 

    MStream :  TMemoryStream; 

begin 

          MStream := TMemoryStream.Create; 

          AStream := TStreamAdapter.Create(MStream);   // tstreamadapter is 

Delphi's wrapper that implements IStream 

          TVarData(vData).vtype := VT_STREAM; 

          TVarData(vData).vpointer := Pointer(AStream as IStream); 

          tmpReturn:= caChart.Export(CHART_CFXOLEFILE, vData); 

end; 

Thanks in advance, 

Gretchen