delphi - 动态创建 Tpagecontrol 实例

Question

我已经搜索和搜索，但没有找到示例。我想动态创建PageControl每个实例都有自己的偏移量TTabsheets .我没有收到来自 Delphi IDE 的任何投诉，但是我确实得到了:

Access violation in module FormApplication.exe write of address 00000000

有什么我想念的吗？

procedure TForm1.FormCreate(Sender: TObject);
type
  ABC_Status_Object = record
    ABC_PageControl_instance: TPageControl;
    quickStat_instance: TTabsheet;
    detailStat_instance: TTabsheet;
    abc_light: TShape;
  end;

var
  ABC_Status: array of ABC_Status_Object;
  I: Integer;
  Frac, Icnt: Extended;

begin
  inifile := TIniFile.Create(ChangeFileExt(Application.ExeName,'.ini'));
  loadGlobalConfig;

  Frac := 100/NUM/100;
  for I := 0 to NUM do
  begin
    {// Create the Tabs: }
    ABC_Status[I].ABC_PageControl_instance := TPageControl.Create(self);
    ABC_Status[I].ABC_PageControl_instance.Parent := self;
    ABC_Status[I].quickStat_instance := TTabsheet.Create(ABC_Status[I].ABC_PageControl_instance);
    ABC_Status[I].detailStat_instance := TTabsheet.Create(ABC_Status[I].ABC_PageControl_instance);
    ABC_Status[I].quickStat_instance.PageControl := ABC_Status[I].ABC_PageControl_instance;
    ABC_Status[I].detailStat_instance.PageControl := ABC_Status[I].ABC_PageControl_instance;

    {// Set the attributes of each instance of PageControl, including the tabs: }
    ABC_Status[I].ABC_PageControl_instance.Visible := TRUE;
    ABC_Status[I].ABC_PageControl_instance.Top := 0;
    if(NUM = 1) then
      ABC_Status[I].ABC_PageControl_instance.Width := ClientWidth;

    if(NUM > 1) AND (NUM < 4) then
    begin
      Icnt := 100/(I+1)/100;

      ABC_Status[I].ABC_PageControl_instance.Width := Trunc(ClientWidth*Frac);
      ABC_Status[I].ABC_PageControl_instance.Left := 30;
    end;
    ABC_Status[I].quickStat_instance.Caption := 'Quick Status';
    ABC_Status[I].quickStat_instance.Visible := TRUE;
    ABC_Status[I].detailStat_instance.Caption := 'Details';
    ABC_Status[I].detailStat_instance.Visible := TRUE;
  end;

end;

Answer 1

您没有分配数组。在访问数组之前，您需要添加以下内容:

SetLength(ABC_Status, NUM+1);

+1是因为您使用了相当非标准的循环边界。

还有 100/100 = 1所以表达式 100/NUM/100看起来很奇怪。你也可以写 1/NUM .

您使用的非标 Extended类型似乎也很奇怪。我认为没有太大必要。

可能还有更多错误，但我在这里停下来。