关于线程的一点疑惑

Question

代码1：unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  TReadThread=class(TThread)
  private
    Faa:string;
  protected
    procedure Execute;override;
  public
    constructor Create(aa:string);
    destructor Destroy; override;
  end;
var
  Form1: TForm1;implementation{$R *.dfm}{ TReadThread }constructor TReadThread.Create(aa: string);
begin
  Faa:=aa;
  FreeOnTerminate:=True;
  inherited Create(false);
end;destructor TReadThread.Destroy;
begin
  Faa:='';
  inherited;
end;procedure TReadThread.Execute;
begin
  form1.Memo1.Lines.Add(Faa);end;procedure TForm1.Button1Click(Sender: TObject);
begin
  TReadThread.Create('asdf');
end;end.这个时候点击按钮向Memo加入‘asdf’没有任何问题
但是在form2上动态创建后会出问题
在form1.Memo1.Lines.Add(Faa);断点看到   form1.Memo1=Inaccessible value
想知道为什么会出现这种结果
unit Unit2;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs,Unit1, StdCtrls;type
  TForm2 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form2: TForm2;
  implementation{$R *.dfm}procedure TForm2.Button1Click(Sender: TObject);
var bb:TForm1;
begin
  bb:=TForm1.Create(self);
  bb.Parent:=Form2;
  bb.Show;
end;end.

Answer 1

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons;type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  TReadThread=class(TThread)
  private
    faa: string;
    FForm: TForm1;
  protected
    procedure Execute;override;
  public
    constructor Create(CreateSuspended: Boolean);
    property aa: string read faa write faa;
    property AForm: TForm1 read FForm write FForm;
  end;var
  Form1: TForm1;implementation{$R *.dfm}constructor TReadThread.Create(CreateSuspended: Boolean);
begin
  inherited Create(false);
end;procedure TReadThread.Execute;
begin
  FreeOnTerminate:=True;
  FForm.Memo1.Lines.Add(Faa);
end;procedure TForm1.Button1Click(Sender: TObject);
var
  rt: TReadThread;
begin
  rt:= TReadThread.Create(false);
  rt.aa:= 'asdf';
  rt.AForm:= self;
  rt.Resume;
end;end.

Answer 2

你的Form2是怎么创建的？注意你的线程是向form1的memo1写数据，不是form2创建的bb中写数据。

Answer 3

你创建的TForm1是bb 线程里的是form1变量还有在线程中操作VCL最好用同步