tchart 跟随鼠标的y轴线

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, TeEngine, TeeTools, Series, ExtCtrls, TeeProcs, Chart, StdCtrls;

type
  TForm1 = class(TForm)
    Chart1: TChart;
    Series1: TLineSeries;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Chart1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
   Series2: TLineSeries;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var i:Integer;
begin
  for   i:=1 to 30 do
    begin
     self.Chart1.Series[0].AddXY(i,2);
      end;

     
end;

procedure TForm1.Chart1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);

var
     XAxis: Integer;

      begin

      XAxis:= Round(Chart1.Series[0].XScreenToValue(X));

      Caption:=IntToStr(XAxis) ;

       Series2.Clear;

   Series2.AddXY(XAxis,3,'',clRed);
   Series2.AddXY(XAxis,0,'',clRed);

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
Series2:= TLineSeries.Create(self);
   Series2.ParentChart:=Chart1;

   Series2.AddXY(2,3,'',clRed);
   Series2.AddXY(2,0,'',clRed);
end;

end.