TEvent.SetEvent 上的 TThread 行为

问：

使用 TThread 和 TEvent 启动线程完成的工作时，我遇到了奇怪的行为。由于暂停/恢复已被弃用，我一直在寻找使用 TEvent，所以这里只是我拥有的简化代码，但它仍然无法按预期执行。我有带有FThreadStartEvent的TSampleThread类。例如，我创建了 TSampleThread 的 3 个实例，但是当我通过在其中设置 FThreadStartEvent 来启动一个线程时，不知何故，所有实例都会被执行。

问题是什么？ 谢谢大家。

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, System.Contnrs, System.SyncObjs,
  Vcl.StdCtrls;


type
  TSampleThread = class;
  TTaskProc = procedure(const SampleThread:TSampleThread) of object;

 TSampleThread = class (TTHread)
  public
   FId:String;
   FThreadStartEvent: TEvent;
   FOnThreadExecute:TTaskProc;
   constructor Create;
   destructor Destroy; override;
   procedure  Execute; override;
   procedure  Start;
 end;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private

    { Private declarations }
  public
    task1, task2, task3:TSampleThread;
    procedure onTask(const SampleThread: TSampleThread);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TSampleThread.Execute;
begin
 repeat
  FThreadStartEvent.WaitFor(INFINITE);
  FThreadStartEvent.ResetEvent;
  if Assigned(TMethod(FOnThreadExecute).Code) then FOnThreadExecute(Self);
 until terminated;

end;


procedure TSampleThread.Start;
begin
 FThreadStartEvent.SetEvent;
end;

constructor TSampleThread.Create;
begin
  FreeOnTerminate:= False;
  FOnThreadExecute:= nil;
  FThreadStartEvent:= TEvent.Create(nil, true, false, 'ThreadStartEvent');
  inherited Create(false);

end;

destructor TSampleThread.Destroy;
begin
   FThreadStartEvent.SetEvent;
   FThreadStartEvent.Free;
   inherited;
end;

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
begin
 task1.Start;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin

  task1:= TSampleThread.Create;
  task1.FId:= 'Task 1' ;
  task1.FOnThreadExecute:= onTask;


  task2:= TSampleThread.Create;
  task2.FId:= 'Task 2' ;
  task2.FOnThreadExecute:= onTask;

  task3:= TSampleThread.Create;
  task3.FId:= 'Task 3' ;
  task3.FOnThreadExecute:= onTask;


end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
 task1.Free;
 task2.Free;
 task3.Free;
end;

procedure TForm1.onTask(const SampleThread: TSampleThread);
begin
  SampleThread.Synchronize(nil,
  procedure
  begin
    Memo1.Lines.Add(SampleThread.FId);
  end);
end;




end.