写了个线程，每隔一秒显示一个数字（每次加一），但不完美

写了个线程，每隔一秒显示一个数字（从0开始，每次加一）。但是发现，有时候会不显示，之后就跳过了这个数字。比如：正常情况下，会从1顺序地显示到8，但是应该显示9的时候，屏幕为空白，之后却显示10了；还有种情况，显示的时候突然为粗体显示，之后又恢复了，我并没有改变过字体字号！

效果图：







我现在把代码全部贴上，请高人帮忙看看错在哪，谢谢！

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Label1: TLabel;
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

TMyThread = class(TThread)
private
{ Private declarations }
FOwner: TForm;
FLastAutoCMDTime: TDateTime;

protected
procedure Execute; override;
public
constructor Create(Owner: TForm); virtual;

end;

var
Form1: TForm1;
FThread:TmyThread ;
FLastAutoCMDTime: TDateTime;
fval:longint ;
implementation

{$R *.dfm}
constructor TMyThread.Create(Owner: TForm);
begin
inherited Create(False);
FOwner := Owner;
FLastAutoCMDTime := Now;
fval:=0 ;
end;

procedure TMyThread.Execute;
begin

while not Terminated do
begin
if MilliSecondsBetween(Now, FLastAutoCMDTime) > 1000 then //每隔1秒
begin
FLastAutoCMDTime := Now;
inc(fval) ;
Tform1(FOwner).Label1.Caption:=inttostr(fval) ;
end ;
end;

end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
if FThread<>nil then
begin
FThread.Terminate;
FThread.WaitFor;
FThread.Free;
end ;

end;

procedure TForm1.FormCreate(Sender: TObject);
begin
FThread:=TMyThread.Create(form1) ;

end;

end.