instance of TppVariable always 0

rbuser

I have a variable named ftr_Total of type TppVariable in my report. I have
set the timing to be ReportEnd (reset) and ReportEnd (calc). This variable
lives in the summary band of my report. The DisplayFormat property is
empty. This is a two-pass report. I have hardcoded the OnCalc event:

procedure TMyDM.ftr_TotalCalc(Sender: TObject; var Value: Variant);
begin
ftr_Total.Value:= 1234; //breakpoint set here
end;

I have also set a breakpoint on the Reset event:

procedure TMyDM.ftr_TotalReset(Sender: TObject; var Value: Variant);
begin
sleep(0); //breakpoint set here too
end;

When I print the report, these breakpoints are reached in this order:
RESET
CALC

To my surprise, the displayed value is ALWAYS zero (0). What is going on
here?

nicocizik

Hi Tyler,

The setting for ReportEnd was mainly designed to be used as a reset flag.
What exactly are you trying to accomplish in your report? (i.e. what value
would you ultimately like displayed in your summary band?)

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Regardless, why would the value be displayed as 0 after 1234 has been
assigned and the reset event never fires again?

Originally, I was trying to sum two values which also live in the summary
band. These two values are of type TppDBCalc and TppDBText:

ftr_Total.Value:= ftr_Subtotal.Value + ftr_Freight.FieldValue;

Unfortunately, if I use the veTraversal for the CalcType property,
ftr_Subtotal.value is ALWAYS zero. That is why I favored the veReportEnd
CalcType, since ftr_Subtotal.value is assigned by that time.

In summary, I have not found a suitable strategy for having a TppVariable
sum a TppDBCalc and TppDBText. A tradeoff exists between the CalcType used
for the TppVariable and the calculated value of the TppDBCalc.

nicocizik

Hi Tyler,

If I understand correctly, you are adding the total sum of one column in
your database to the last record in a different colunm? In my testing the
following method worked correctly.

1. Create three TppVariables, one located in the detail band and two in the
summary.
2. Inside the OnCalc of the first variable in the detail band, update the
value of the second variable with the sum of the data field.
3. Inside the OnCalc of the second varible, add it's current total to the
last record in your dataset.

All three variables are set to reset on ReportEnd and calc on Traversal.

Code...

procedure TForm1.ppVariable1Calc(Sender: TObject; var Value: Variant);
begin
ppVariable2.Value := ppVariable2.Value +
ppReport1.DataPipeline['AmountPaid'];
end;

procedure TForm1.ppVariable2Calc(Sender: TObject; var Value: Variant);
begin
ppVariable3.Value := Value + ppReport1.DataPipeline['AmountPaid'];
end;

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com