如何防止Firemonkey复合组件中的子组件重复？ [英] How can I prevent duplication of sub components in Firemonkey compound component?

问题描述

我正在尝试编写一个从TDummy派生的复合组件。组件来源为：

I am trying to write a compound component which is derived from TDummy. The component source is:

  TMyObjectType=(otCube,otSphere);
  TMyGameObject=class(TDummy)
  private
    FObj:TCustomMesh;
    FMyObjectType: TMyObjectType;
    procedure SetMyObjectType(const Value: TMyObjectType);
  public
    constructor Create(AOwner:TComponent);override;
    destructor Destroy;override;
    property MyObjectType:TMyObjectType read FMyObjectType write SetMyObjectType;
  end;

{ TMyGameObject }

constructor TMyGameObject.Create(AOwner: TComponent);
begin
  inherited;
  MyObjectType:=otCube;
end;

destructor TMyGameObject.Destroy;
begin
  FObj.Parent.RemoveObject(FObj);
  FreeAndNil(FObj);
  inherited;
end;

procedure TMyGameObject.SetMyObjectType(const Value: TMyObjectType);
begin
  FMyObjectType := Value;
  if(Assigned(FObj))then begin
    FObj.Parent.RemoveObject(FObj);
    FreeAndNil(FObj);
  end;
  case FMyObjectType of
    otCube: FObj:=TCube.Create(Self);
    otSphere: FObj:=TSphere.Create(Self);
  end;
  FObj.SetSubComponent(True);
  FObj.Parent:=Self;
end;

将MyObjectType更改为otSphere。

after I register the component and put one instance on a TViewport3D in the code of a Tbutton I try to change the MyObjectType to otSphere.

MyGameObject1.MyObjectType:=otSphere;

但似乎没有任何反应。所以我写了一段代码作为休假代码。

but it seems there is nothing happening. So I wrote a piece of code as fallow.

procedure MyParseObj(obj:TFmxObject;var s:string);
var
  i: Integer;
  a:string;
begin
  s:=s+obj.ClassName+'(';
  a:='';
  for i := 0 to obj.ChildrenCount-1 do begin
    s:=s+a;
    MyParseObj(obj.Children.Items[i],s);
    a:=',';
  end;
  s:=s+')'
end;

并在另一个按钮中调用它。

and call it in another button.

procedure TForm1.Button2Click(Sender: TObject);
var s:string;
begin
  s:='';
  MyParseObj(myGameObject1,s);
  ShowMessage(s);
end;

结果很奇怪。
，如果我按下button2的结果是：TMyGameObject（TCube（），TCube（））

the result was strange. if I press the button2 result is: TMyGameObject(TCube(),TCube())

，当我按下button1之后，按下button2的结果是：TMyGameObject（TCube（），TSphere（））

and when I press the button1 and after that press button2 result is: TMyGameObject(TCube(),TSphere())

为什么在我的对象中有两个TCustomMesh作为子对象？ （TCube和TSphere是从TCustomMesh派生的）
我该如何解决？

why there is two TCustomMesh as child in my object? (TCube and TSphere are derived from TCustomMesh) how can I fix this?

我还有另一个测试。如果我没有在设计时创建对象，它将正常工作。如果我将TMyGameObject实例放在设计时间中，则会发生问题。

and there is another test that I performed. if I create the object not in design time it work properly. problem happens if I put an instance of TMyGameObject in design time.

推荐答案

保存表单时（从IDE中）所有控件及其所有子级均被保存。如果您的控件创建了自己的子代，则需要设置Stored = False来防止它们被IDE流化。

When you save a form (from the IDE) all controls and all their children are saved. If your control creates it's own children then you need to set Stored = False to prevent them being streamed by the IDE.

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