调用LoadChartFromFile后向TChart添加值触发访问违规错误

当使用LoadChartFromFile加载图表时，它会完全替换Chart中原有的所有Series，包括你在设计时创建的Series1。此时原来的Series1对象已经被销毁，内存地址失效，后续再通过Series1添加数据就会触发访问违规。

不要直接依赖设计时创建的Series变量，而是从Chart的SeriesList中获取当前有效的Series对象。具体修改如下：

1. 统一按钮点击事件逻辑 #

所有添加数据的按钮事件，改为从Chart1.Series集合中获取当前有效的Series实例，避免访问已失效的Series1变量：

procedure TForm7.Button1Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  // 先判断Chart中是否存在Series，避免空指针
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(40);
  end;
end;

其他按钮（Button2到Button5）只需修改Add的数值，逻辑完全一致。

2. 优化加载逻辑（可选） #

在FormCreate中增加文件存在判断，避免首次启动时加载不存在的文件导致异常：

procedure TForm7.FormCreate(Sender: TObject);
begin
  if FileExists('File1') then
    LoadChartFromFile(TCustomChart(Chart1), 'File1');
end;

unit Unit7;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, VclTee.TeeGDIPlus, VCLTee.TeEngine,
  VCLTee.Series, Vcl.ExtCtrls, VCLTee.TeeProcs, VCLTee.Chart, VCLTee.TeeStore, VCLTee.TeeEdiSeri,
  Vcl.StdCtrls;

type
  TForm7 = class(TForm)
    Chart1: TChart;
    Series1: TBarSeries;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form7: TForm7;

implementation

{$R *.dfm}

procedure TForm7.Button1Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(40);
  end;
end;

procedure TForm7.Button2Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(90);
  end;
end;

procedure TForm7.Button3Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(10);
  end;
end;

procedure TForm7.Button4Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(50);
  end;
end;

procedure TForm7.Button5Click(Sender: TObject);
var
  CurrentSeries: TBarSeries;
begin
  if Chart1.SeriesCount > 0 then
  begin
    CurrentSeries := TBarSeries(Chart1.Series[0]);
    CurrentSeries.Add(140);
  end;
end;

procedure TForm7.FormCreate(Sender: TObject);
begin
  if FileExists('File1') then
    LoadChartFromFile(TCustomChart(Chart1), 'File1');
end;

procedure TForm7.FormDestroy(Sender: TObject);
begin
  SaveChartToFile(Chart1,'File1',True);
end;

end.

• 加载图表后，原设计时的Series1已被销毁，必须通过Chart1.Series[index]获取当前有效的Series实例。
• 添加SeriesCount判断是为了处理首次启动且无保存文件的场景，避免空指针异常。

内容的提问来源于stack exchange，提问作者Gustavo Fonseca