Application.ProcessMessages

//如果有这样一个循环, 是非常可怕的; 因为它完不了, 你得等着.

procedure TForm1.Button1Click(Sender: TObject);

var

i: Integer;

begin

for i := 0 to MaxInt do

begin

Text := IntToStr(i);

end;

end;/

/即使这样也无济于事, 因为在循环期间你执行不了Button2Click

var

b: Boolean;

procedure TForm1.Button1Click(Sender: TObject);

var

i: Integer;

begin

b := True;

for i := 0 to MaxInt do

begin

if b then

Text := IntToStr(i)

else

Exit;

end;

end;

procedure TForm1.Button2Click(Sender: TObject);

begin

b := False;

end;

//如果在循环期间...

for i := 0 to MaxInt do

begin

if b then

Text := IntToStr(i)

else

Exit;

{看看还有其他什么事情发生}

end;

//Application.ProcessMessages 就是干这个的!

var b: Boolean;

procedure TForm1.Button1Click(Sender: TObject);

var

i: Integer;

begin

b := True;

for i := 0 to MaxInt do

begin

if b then

Text := IntToStr(i)

else

Exit;

Application.ProcessMessages;

{!}

end;

end;

procedure TForm1.Button2Click(Sender: TObject);

begin

b := False;

end;