delphi – 如何从提供类名的字符串创建实例？

见“Is there a way to instantiate a class by its name in Delphi?”

我试图将任何对象的已发布属性保存到XML文件(工作正常),最近我想从XML文件中重新创建这些对象.在这个文件中写入了应该创建哪个类(例如TButton),然后是一个属性列表,这些属性应该加载到这个运行时创建的对象中.

上面的示例显示了如何执行此操作的方法,但它不适用于我自己的类.见下面的代码：

TTripple=class (TPersistent)
    FFont:TFont;
  public
    constructor Create;
    Destructor Destroy;override;
  published
    property Font:TFont read FFont write  FFont;
  end;
var
  Form1: TForm1;


implementation

{$R *.dfm}

constructor TTripple.Create;
  begin
  inherited;
  FFont:=TFont.Create;
  end;


destructor TTripple.Destroy;
  begin
  FFont.Free;
  inherited;
  end;

procedure TForm1.FormCreate(Sender: TObject);
begin
RegisterClasses([TButton,TForm,TTripple]);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  CRef : TPersistentClass;
  APer : TPersistent;
begin
 // CRef := GetClass('TButton');
  CRef := GetClass('TTripple');
  if CRef<>nil then
  begin
     APer := TPersistent(TPersistentClass(CRef).Create);
     ShowMessage(APer.ClassName);  // shows TTripple,what is correct
     if APer is TTripple then (APer as TTripple).Font.Color:=90;

     /// Here  I get error message,because TTriple was not created... ?!?!?!

  end;
end;

我无法通过.可能已创建TTripple对象,但未使用其构造函数.