I had 'Canvas does not allow drawing'

rbuser

Hi,

I had a report that I was creating programmatically that had 2 subreports
with child reports in them and fields in each. When I ran it a I got to the
first field in the second child report it would report that the 'Canvas does
not allow drawing'. I tracked to the AutoSize:=true in the create of the
ppcustomlabel. When it does this assignment it goes and gets a handle for
the printer canvas and fails because it is returning a zero.

I had for my code to create the childreport:

ASubReport:=TppSubReport.Create(Self);
ASubReport.Band:=MainReport.DetailBand;

AChildReport:=TppChildReport.Ceate(Self);
AChildReport.Parent:=ASubReport;

ALabel:=TppLabel.Create(Self);
etc.

I found a tip that created the child report differently. It had:


ASubReport:=TppSubReport.Create(Self);
ASubReport.Band:=MainReport.DetailBand;

ASubReport:CreateReport(MainReport); //<<
AChildReport:=TppChildReport(ASubReport.Report); //<<

ALabel:=TppLabel.Create(Self);
etc.

This solved the problem. I'm not sure why. If you see this problem, try
looking for this.

Thanks,

Joseph Gordon

digitalmetaphors

There is a demo which shows how to create subreports dynamically:

http://www.digital-metaphors.com/tips/DynamicSubreportCreation.zip


Cheers,

Jim Bennett
Digital Metaphors