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How to load a ClientDataSet in Delphi from a Resource file?

I have a CDS file called PAYGHeadings.cds, which is referenced in a CB.rc file as PAYGHeadings RCDATA system\PAYGHeadings.cds.

The form has an embedded ClientDataSet of cdsPAYGHeadings.

The .RES file seems to be OK, and with the link in the .dpr as {$R 'CB.res' 'CB.rc'}.

So far so good.

Here is the relevant code:

function TfDB.ActivatePAYGHeadings: boolean;
var
  ResStream: TResourceStream;
begin
  try
    ResStream := TResourceStream.Create(hInstance, 'PAYGHeadings', RT_RCDATA);
    cdsPAYGHeadings.LoadFromStream(Resstream);
    cdsPAYGHeadings.IndexDefs.Clear;
    with cdsPAYGHeadings.IndexDefs.AddIndexDef do
    begin
      Name := 'MainIdx';
      Fields := 'EffectiveDate, Scale';
      Options := [ixUnique];
    end;
    cdsPAYGHeadings.IndexName := 'MainIdx';
    result := true;
  except
    screen.cursor := crDefault;
    fDiagnosis.eTable.text := 'PAYGHeadings';
    fDiagnosis.showModal;
    result := false;
    exit;
  end;
end;

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The CDS has a primary index of EffectiveDate and Scale;

Yet the code fails on assigning the IndexName.

I suspect I am missing a line or two of code, but I can't fathom the logic of how to set up the appropriate pointers.

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developmentguru

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GrahamDLovell

ASKER

Thanks developmentguru for your response.

Yes, it is a binary file, and it can be loaded normally.

Can you give me your "loading from XML in a resource" code? That would provide a satisfactory solution to my problem, although it would be nice to understand the correct way to set up the stream (which obviously I have got wrong).

I have not previously loaded data from a resource file.

GrahamDLovell

ASKER

Further work on developmentguru's suggestion.

I just got the Fields assignment wrong.

In the code cited I had Fields := 'EffectiveDate, Scale';

The fields should have been separated by a semi-colon, not by a comma.

My Stream assignments were obviously OK.