Question

场景： 用户随机按开始按钮几次，然后必须停止所有产生的线程（单击TerminateButton）。

问题： 如何正确终止/等待/释放用户执行的所有线程？

通常，如果我必须运行指定数量的线程，我只会使用线程数组，然后对数组中的所有项目循环.terminate / .waitfor / free。但是在这种情况下，我无法执行此操作，因为未确定线程数。

procedure TForm1.StartButtonClick(Sender: TObject);
begin

  WorkerThread:=TWorkerThread.Create(true);
  WorkerThread.FreeOnTerminate:=false;
  WorkerThread.Resume;

end;

procedure TWorkerThread.Execute;
begin

  repeat
    //some code here
  until Terminated=true;

end;

procedure TForm1.TerminateButtonClick(Sender: TObject);
begin

  if Assigned(WorkerThread)=true then // <-This will work only for last instance
  begin
    WorkerThread.terminate;           // <-This will work only for last instance 
    WorkerThread.waitfor;             // <-This will work only for last instance 
    FreeAndNil(WorkerThread);         // <-This will work only for last instance 
  end;

end;

Answer 1

此刻，我将所有线程存储在TList中。此示例代码似乎可以正常工作。

procedure TForm1.FormCreate(Sender: TObject);
begin
  InitializeCriticalSection(CriticalSection);
  ThreadList:=TList.Create;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  DeleteCriticalSection(CriticalSection);
end;

procedure TForm1.StartButtonClick(Sender: TObject);
begin

  EnterCriticalSection(CriticalSection);  //<- This will be required in my real multithreaded code

  WorkerThread:=TWorkerThread.Create(true);
  ThreadList.Add(WorkerThread);
  WorkerThread.FreeOnTerminate:=false;
  WorkerThread.OnTerminate:=form1.ThreadTerminated;
  WorkerThread.Resume;

  LeaveCriticalSection(CriticalSection);

end;

procedure TWorkerThread.Execute;
begin

  repeat
    sleep(random(1000));
  until Terminated=true;

end;

procedure TForm1.ThreadTerminated(Sender: TObject);
begin
  form1.Memo1.Lines.Add('terminated');
end;


procedure TForm1.TerminateButtonClick(Sender: TObject);
var x:integer;
begin

  form1.Memo1.Clear;
  EnterCriticalSection(CriticalSection);  //<- This will be required in my real multithreaded code

  for x:=0 to ThreadList.Count-1 do
  begin

    if Assigned(ThreadList.Items[x])=true then
    begin
      WorkerThread:=ThreadList.Items[x];
      WorkerThread.Terminate;
      WorkerThread.waitfor;
      FreeAndNil(WorkerThread);
    end;

  end;

  ThreadList.Clear;

  LeaveCriticalSection(CriticalSection);

end;

如何终止并释放用户产生的随机数量的线程？

1 个答案: