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Ticket T1284214
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DataController.Summary.FooterSummaryItems how to tell Footer from GroupFooter?

created 5 days ago

Hello,

  1. I want to do different calculations depending on the footer vs GroupFooter type of summary but within the event method, I don't know how to tell the difference. I can play with the tags but I'd prefer to be able to identify the type of summary.

  2. More problematic: I have used this article to hide one of the groupfooters. This is working correctly (at the price of a bigger complexity) but I am not able to do custom calculations.

As a reminder, on that article, we create a subclass of TcxDBBandedTableView (and a few other classes) and do something like this in the OnCreate event of the form:

Delphi
AView := GRoyalties.CreateView(TcxMyGridDBBandedTableView) as TcxMyGridDBBandedTableView;
AView.AssignPattern(vRoyalties);
GRoyaltiesLevel2.GridView := AView;

My custom calculation code is this:

Delphi
procedure TFAgreement.vRoyaltiesDataControllerSummaryFooterSummaryItemsSummary(
  ASender: TcxDataSummaryItems; Arguments: TcxSummaryEventArguments;
  var OutArguments: TcxSummaryEventOutArguments);
var
  AValue,BaseRedev: Variant;
  IsSelected: Variant;
  AItem: TcxGridTableSummaryItem;
  avirer:String;
begin
  AItem := TcxGridTableSummaryItem(Arguments.SummaryItem);
  if (AItem.Tag > 0) and (AItem.Position = spFooter) then begin
    avirer:=TcxGridDBBandedColumn(aitem.Column).DataBinding.FieldName;
    if avirer='s' then
      write;
    AValue := TcxGridDBBandedTableView(GRoyalties.FocusedView).DataController.Values[ Arguments.RecordIndex, AItem.Column.Index ];
    BaseRedev := TcxGridDBBandedTableView(GRoyalties.FocusedView).DataController.Values[ Arguments.RecordIndex, TcxGridDBBandedTableView(GRoyalties.FocusedView).GetColumnByFieldName('baseredevance').Index ];
    if not VarIsNull(AValue) and not VarIsNull(BaseRedev) then
      OutArguments.Value:=AValue*BaseRedev/100
    else
      OutArguments.Value:=0;
    OutArguments.value:=18;
  end
end;

The AItem.tag for this particular GroupFooter summary is 2

The avirer variable is here for debugging purposes and always contains "idad" which is a field that is not used in any summary. So my guess is that the Arguments.SummaryItem points to something wrong.
As you can see, I am assigning the value 18 to OutArguments.value but I never see this value in any Summary although the program correctly stops on the breakpoint that I set on the line if avirer='s' then.

I hope you can help me understand what is going on.
Thanks in advance.

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Answers approved by DevExpress Support

created 4 days ago

Hello,

Thank you for the details.

Basically, you can use the following API members to determine a column and the current summary item's position:

Delphi
procedure TForm2.tvSampleDataControllerSummaryDefaultGroupSummaryItemsSummary(
  ASender: TcxDataSummaryItems; Arguments: TcxSummaryEventArguments;
  var OutArguments: TcxSummaryEventOutArguments);
begin
  //use Arguments.SummaryItem.ItemLink.ClassName to check the real class name
  //e.g. TcxGridDBBandedColumn
  Memo1.Lines.Add(TcxGridDBColumn(Arguments.SummaryItem.ItemLink).Name);
  if Arguments.SummaryItem.Position = spGroup then
    Memo1.Lines.Add('Group')
  else
    Memo1.Lines.Add('Footer');
end;

Since the event is handled at the DefaultGroupSummaryItems level, all items are at the groups level.

If you wish to use a single handler for DefaultGroupSummaryItems and FooterSummaryItems, you can create a separate function, e,g.:

Delphi
procedure TForm2.DoSummary(ASender: TcxDataSummaryItems;
  Arguments: TcxSummaryEventArguments;
  var OutArguments: TcxSummaryEventOutArguments; IsGroup: Boolean);
begin

  //custom calculations
end;

procedure TForm2.tvSampleDataControllerSummaryDefaultGroupSummaryItemsSummary(
  ASender: TcxDataSummaryItems; Arguments: TcxSummaryEventArguments;
  var OutArguments: TcxSummaryEventOutArguments);
begin
  DoSummary(ASender, Arguments, OutArguments, True);
end;

procedure TForm2.tvSampleDataControllerSummaryFooterSummaryItemsSummary(
  ASender: TcxDataSummaryItems; Arguments: TcxSummaryEventArguments;
  var OutArguments: TcxSummaryEventOutArguments);
begin
  DoSummary(ASender, Arguments, OutArguments, False);
end;

If you still encounter issues, please illustrate your current implementation in a deployable project that uses our TdxMemData as a dataset. We will look for a more precise solution.

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