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Report From: Delphi-BCB/Midas/TClientDataSet [ Add a report in this area ]

Report #: 1712

Status: Closed

TFieldAggregate returns incorrect value

Project: Delphi

Build #: 6.240

Version: 6.0

Submitted By: Dave Rowntree

Report Type: Minor failure / Design problem

Date Reported: 7/3/2002 4:09:47 AM

Severity: Serious / Highly visible problem

Last Updated: 12/15/2006 4:02:56 AM

Platform: 95, 98, 2000, NT, XP

Internal Tracking #: 140326

Resolution: Fixed (Resolution Comments)

Resolved in Build: : 7.0.8.1

Duplicate of: None

Voting and Rating

Overall Rating: (7 Total Ratings)

3.86 out of 5

Total Votes: None

Description

A TFieldAggregate returns an incorrect value if you set a CDS filter, then unset the filter. The value then returned by the TAggregateField.Value is the sum of the CDS filtered value and the CDS unfiltered value.

Steps to Reproduce:

Run the attached program and follow the on-screen instructions.

Workarounds

Add the following procedure to your app. Whenever there is a change to a CDS filter, or a change to an index when a filter is/has been used, call the procedure, passing the CDS to it.

type
  TCrackCDS = class(TCustomClientDataSet);
procedure ResetAggFieldsAndAggs(CDS:TClientDataSet);
var
  i: integer;
  Agg: TAggregate;
begin
  // do the AggFields ...
  for i := 0 to CDS.AggFields.Count - 1 do
  begin
    Agg := (CDS.AggFields[i] as TAggregateField).Handle;
    if (Agg <> nil) and Agg.Active then
    begin
      Agg.Active := False;
      Agg.Active := True;
    end;
  end;
  // do the Aggs ...
  for i := 0 to CDS.Aggregates.Count - 1 do
  begin
    Agg := CDS.Aggregates[i];
    if Agg.Active then
    begin
      Agg.Active := False;
      Agg.Active := True;
    end;
  end;
  TCrackCDS(CDS).DataEvent(deRecordChange, 0);
end;

---------

This is Dave's workaround:

Add the following procedure to your app. Whenever there is a change to a CDS filter, or a change to an index when a filter is/has been used, call the procedure, passing the CDS to it.

procedure ResetAggFieldsAndAggs(CDS:TClientDataSet);
var
  i: integer;
  Agg: TAggregate;
begin
  // do the AggFields ...
  for i := 0 to CDS.AggFields.Count - 1 do
  begin
    Agg := (CDS.AggFields[i] as TAggregateField).Handle;
    if (Agg <> nil) and Agg.Active then
    begin
      Agg.Active := False;
      Agg.Active := True;
    end;
  end;
  // do the Aggs ...
  for i := 0 to CDS.Aggregates.Count - 1 do
  begin
    Agg := CDS.Aggregates[i];
    if Agg.Active then
    begin
      Agg.Active := False;
      Agg.Active := True;
    end;
  end;
end;

Attachment

FieldAggregateFilterbug.zip

Comments

Dave Rowntree at 5/11/2004 2:39:11 AM -

Fixed in Midas.dll

Joao Toledo at 7/1/2004 1:45:39 PM -

The problem persists with DBExpress!

I tried the attached project with MIDAS.DLL 7.1.1523 and your patch, and it worked well. But when I tried it with connection via DBExpress, the problem still is there.

Dave Rowntree at 7/21/2004 3:36:39 AM -

The problem was fixed in the the D7.1 update, Midas.dll version 7.1.1692.666.

The Midas.dll version you are using does not contain the fix. You can obtain the updated Midas.dll version from www.distribucon.com.

You do not need to use the workaround as well as the fixed Midas.dll version, just use the updated Midas.dll.

Joao Toledo at 7/21/2004 5:50:10 AM -

Thank you very much!

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