DBCHART MouseMove 取X轴日期类型数值问题

新建DBCHART 未做任何设置窗体新建代码
var s1:TLineSeries;
begin
    s1:= TLineSeries.Create(dbchart1);
    s1.Add(1,'2008-5-1 1:00:00');
    s1.Add(2,'2008-5-1 2:00:00');
    s1.Add(3,'2008-5-1 3:00:00');
    s1.Add(1,'2008-5-1 1:00:00');
    s1.Pointer.Visible:=true;
    dbchart1.AddSeries(s1);
end;dbchart MOUSEMOVE 代码
procedure TForm1.dbchart1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var AValueIndex,i:Integer;
begin
    for i:=0 to dbchart1.SeriesCount-1 do
    begin
        t:=dbchart1.Series[i].Clicked(x,y);
        if t<>-1 then
        begin
            AValueIndex:=dbchart1.Series[i].GetCursorValueIndex;
            if AValueIndex>-1 then
            begin
                Label1.Visible:=True;
                Label1.Top:=Y+20;
                Label1.Left:=X;
                Label1.Caption:=FloatToStr(dbchart1.Series[i].YValue[AValueIndex]);
                Label1.Caption:=Label1.Caption+'-'+FloatToStr(dbchart1.Series[i].XValue[AValueIndex]);
            end
            else
            begin
                Label1.Visible:=False;
            end;
        end;
    end;
end;问题是取X轴值显示 POINT的序号 无法正确取得日期信息,请各位高手HELP 拜谢~