TeeChart. Draw grid lines on the top of Gantt series

Question

I am using Gantt series to show regions on a chart. The problem is that the series is drawn on the top of the chart grid.

I would like the normal line series to be drawn on the top of the grid and Gantt series behind it. Is it possible with standard TChart features, without OnAfterDraw?

Answer 1

You could draw the TGanttSeries at OnBeforeDrawAxes, then hide it at OnBeforeDrawSeries and finally make it visible again at OnAfterDraw for the next drawing cycle:

type
  TForm1 = class(TForm)
    Chart1: TChart;
    Series1: TGanttSeries;
    Series2: TLineSeries;
    procedure FormCreate(Sender: TObject);
    procedure Chart1BeforeDrawAxes(Sender: TObject);
    procedure Chart1BeforeDrawSeries(Sender: TObject);
    procedure Chart1AfterDraw(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

type TCustomSeriesAccess=class(TCustomSeries);

procedure TForm1.Chart1BeforeDrawAxes(Sender: TObject);
begin
  TCustomSeriesAccess(Series1).DrawAllValues;
end;

procedure TForm1.Chart1BeforeDrawSeries(Sender: TObject);
begin
  Series1.Visible:=False;
end;

procedure TForm1.Chart1AfterDraw(Sender: TObject);
begin
  Series1.Visible:=True;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chart1.Draw;
end;