Request to expose IsValidDataSource for override

[Liang]

Hello

I am now using BDS2006 C++Builder, with TeeChart 2010 Pro.

Currently, according to example, I need to define a new class derived from TDBChart with IsValidDataSource overridden to have some dataset hidden.

This is very complicated, according to demo, all must be programmed to be created run-time, and many coding work. And also I have headache for cross-unit datasets namespace problems.

Is it possible for TDBChart to expose this IsValidDataSource, so I can do in such a way to have an easy override?

1. Create a new event called OnValidDataSource to pass parameters out for user to further changing -->preferred
or
2. Directly expose the function address of IsValidDataSource for overriding.-->not perferred.

[Yeray]

Hi Liang,

I've added your request to the wish list to be studied for inclusion in next releases (TV52015116).

[Liang]

Hello

I have implemented such exposure of OnValidDataSource event. And it works fine.

Now I can make my software more clean, with only desired DataSet shown to user at run-time.

I would like to contribute my modification on DBChart.pas to you. Please check it:

line 48

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  TValidDataSourceEvent=Procedure(Sender:TCustomDBChart; ASeries:TChartSeries; AComponent:TComponent;
    var Valid:Boolean) of object;

line 57:

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    FOnValidDataSource:TValidDataSourceEvent;

line 91:

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    property OnValidDataSource:TValidDataSourceEvent read FOnValidDataSource
                                                 write FOnValidDataSource;

line 104:

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    property OnValidDataSource;

line 488:

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Function TCustomDBChart.IsValidDataSource(ASeries:TChartSeries; AComponent:TComponent):Boolean;
var
  BoolValue:Boolean;
Begin
  BoolValue:=inherited IsValidDataSource(ASeries,AComponent);
  if not BoolValue then BoolValue:=(AComponent is TDataSet) or (AComponent is TDataSource);
  if Assigned(FOnValidDataSource) then
  begin
    FOnValidDataSource(Self,ASeries,AComponent,BoolValue);
  end;
  Result:=BoolValue;
end;

[Narcís]

Hello Liang,

Thank you very much for your contribution. We will analyse it and get back to you as soon as possible.

[Narcís]

Hi Liang,

I think you can already override IsValidDataSource as in the examples in this thread. The projects Jørgen posted already derive a class from TDBChart and override IsValidDataSource method. Does this fit your needs?

[Liang]

Hello

I think mine is different, and prefer my way.

My solution is to expose the event of ValildDataSource on the TDBChart level, so I can directly in my source code, catch this event from the TDBChart component, and override the result by user as

Code: Select all

 void __fastcall TScriptFrame::ResultDBChartValidDatasource(
      TCustomDBChart *Sender, TChartSeries *ASeries, TComponent *AComponent,
      bool &Valid)
{
  Valid=(AComponent==DataSource->DataSet);
}
//---------------------------------------------------------------------------

So the freedom is at the user side.

[Narcís]

Hi Liang,

Ok, we implemented this for next maintenance release.