多线程改变窗口标题

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    grp1: TGroupBox;
    edt1: TEdit;
    btn1: TButton;
    btn2: TButton;
    btn3: TButton;
    btn4: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure btn3Click(Sender: TObject);
    procedure btn4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  MyThreadID: DWORD ;//多线程ID
  MyThread: THandle; //多线程句柄

implementation

{$R *.dfm}


{多线程函数}
procedure  MyFunction();//线程要执行的函数
var i:integer;
begin
  for i := 0 to 200000 do //循环改变窗口标题
  Form1.Text := IntToStr(i);
end;
{开始}
procedure TForm1.btn1Click(Sender: TObject);
begin
  MyThread:=createthread(nil,0,@MyFunction,nil,0,MyThreadID); //创建线程并立即执行
  if MyThread = 0 then
  ShowMessage('多线程创建失败');
end;
{挂起}
procedure TForm1.btn2Click(Sender: TObject);
begin
  suspendthread(MyThread);//挂起线程
end;
{继续}
procedure TForm1.btn3Click(Sender: TObject);
begin
  ResumeThread(MyThread);//恢复线程
end;
{结束线程}
procedure TForm1.btn4Click(Sender: TObject);
begin
  TerminateThread(MyThread,2);//结束线程
end;

end.