Excel spreadsheet remains locked after viewing report

[merceng]

Hi all.

I have a problem with a report that uses Excel as a datasource.

I am using Crystal XI Professional, Delphi 7 and Excel 2002.

I have a Delphi application which uses the Crystal Reports viewer control to preview a report. The report displays OK, but when I close the form containing the control, I find that the Excel spreadsheet remains locked.

I am using the following code:

crReport := Application1.OpenReport(extractfilepath(forms.Application.ExeName) + 'Reports\Machine Scheduling.rpt',crOpenReportByTempCopy);
crReport.DiscardSavedData;

crReport.ParameterFields.GetItemByName('MachineCentre','').AddCurrentValue('CNC Turn') ;

CRViewer1.EnableExportButton := true;
CRViewer1.EnableGroupTree := false;
CRViewer1.ReportSource := crReport;
CRViewer1.ViewReport;

In the Form's OnClose event I have the following:

crReport._Release;
crReport := nil;

I've also tried adding:

Application1 := nil;

But this doesn't seem to make any difference!

I assume I'm missing a piece of code that will force Crystal to release the file?

Any help would be greatly appreciated.

Thanks in advance.

Dave