TThread自终止，是否需要带有析构函数的OnTerminate？

Question

我有一个线程类来做一些工作，然后将消息发布到主应用线程并自行终止。正确的方法是什么，我需要一个OnTerminate过程还是Destructor足够？

（线程列表与问题无关，我想用它来检查有多少线程仍在工作）

FThread := TPicBuilder.Create(PicObject);
FThread.Resume;

。

Type TPicBuilder = class(TThread)
  protected
    procedure Execute; override;
  private
    MyPic: TBitmap32;
    procedure AddToPool;
    procedure RemoveFromPool;
    procedure MyTerminateHandler(Sender: TObject);
  public
    Constructor Create(Pic: Pointer);
    Destructor Destroy; override;
end;

Var PicThreads: TObjectList<TPicBuilder>;

implementation

Constructor TPicBuilder.Create(Pic: Pointer);
begin
  inherited Create(False);
  Self.FreeOnTerminate := True;
  Self.OnTerminate := MyTerminateHandler;
  MyPic:= TBitmap32(Pic);
  Synchronize(AddToPool);
end;

Destructor TPicBuilder.Destroy;
begin
  inherited Destroy;
  Synchronize(RemoveFromPool);
  // PostMessage(Application.Handle, WM_APicBuilt, 0 {some tag goes here with a pic ID}, 0); // should I call this here instead?
end;

procedure TPicBuilder.AddToPool;
begin
  PicThreads.Add(Self);
end;

procedure TPicBuilder.RemoveFromPool;
begin
  PicThreads.Remove(Self);
end;

procedure TPicBuilder.MyTerminateHandler(Sender: TObject);
begin
  PostMessage(Application.Handle, WM_APicBuilt, 0, 0);
end;

Procedure TPicBuilder.Execute;
begin
  // thread work
end;

Initialization
  PicThreads := TObjectList<TPicBuilder>.Create(False);

Finalization
  PicThreads.Free;

end.