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Bug 2683

Summary: MouseWheel Scrolling doesn't trigger OnScroll
Product: VCL TeeChart Reporter: yeray alonso <yeray>
Component: ChartAssignee: yeray alonso <yeray>
Status: RESOLVED FIXED    
Severity: enhancement CC: yeray
Priority: ---    
Version: 39.231109   
Target Milestone: ---   
Hardware: PC   
OS: Windows   
URL: https://www.steema.com/support/viewtopic.php?f=3&t=10369
Chart Series: --- Delphi / C++ Builder RAD IDE Version:

Description yeray alonso 2024-03-07 07:22:09 EST 
As the customer explains in the forums, scrolling with the mouse wheel doesn't trigger the OnScroll event.

Note it is triggered when using the TAxisArrowTool and the TAxisScrollTool.

Example using a memo to see how many times the OnScroll event is triggered:

uses Chart, Series, TeeProcs, TeeTools;

var Chart1: TChart;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chart1:=TChart.Create(Self);

  with Chart1 do
  begin
    Parent:=Self;
    Align:=alClient;
    Color:=clWhite;
    Gradient.Visible:=False;
    Walls.Back.Color:=clWhite;
    Walls.Back.Gradient.Visible:=False;
    Legend.Hide;
    View3D:=False;

    AddSeries(TLineSeries).FillSampleValues;

    OnScroll:=ChartOnScroll;

    with TAxisArrowTool(Tools.Add(TAxisArrowTool)) do
    begin
      Axis:=Axes.Left;
    end;

    with TAxisScrollTool(Tools.Add(TAxisScrollTool)) do
    begin
      Axis:=Axes.Bottom;
    end;
  end;

  Memo1.Clear;
end;

procedure TForm1.ChartOnScroll(Sender: TObject);
begin
  Memo1.Lines.Add('onscroll');
end;