I have a Form with several controls. Because of several reasons I am rearranging all the components on the form while the program is running. Unfortunately this has the effect, that the more controls I am changing and the slower the machine is the easier I can see the 'moving' and the form is flickering. So I want to do the changes in the background.
When I had similar problems with drawing into a drawbox I just used the Visible-property.
So I tried this also here
Form.Visible := false;
RearrangingMyControls;
Form.Visible := true;
unfortunately the last one is calling the FormShow, what I cannot need.
Now I could override the Visible property and set a variable SkipFormShow : boolean to control that. But then I have to write in every Form at the beginning of every FormShow procedure a line like
if SkipFormShow then exit;
I have my own class tMyForm of tForm. But all what I tried, to control from there, whether to jump into the childs FormShow or not, failed.
What is the easiest way to have the logic in my basic class tMyForm?
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guessing, no delphi on hand yet,
you have assigned an onFormShow-event
you could deasssign this event, do your action and reassign again like
var
m : TNotifyEvent, //not in mind yet, which is correct method-type
begin
m := onFormShow;
onFormShow := nil;
try
Visible := false;
RearrangingMyControls;
Visible := true;
finally
onFormShow := m;
end;
end;
just as idea
meikl ;-)
Hi!
Instead of change the Visible property of the form, you can disable its redraw sending the mesage Wm_SetRedraw
An example:
procedure TForm1.Button2Click(Sender
var
n : integer;
begin
//Disable redraw
Form1.Perform(WM_SetRedraw
//Do some stuff with the components:
for n:=0 to 50 do begin
Button2.Left:=Button2.Left
Sleep(100);
end;
//Re-enable it
Form1.Perform(WM_SetRedraw
end;
A couple of suggestions. They are more complicated then just turning the visible property on or off but they work. Both of them, if you do them right, should allow the form to appear unchanged until the final arrangement is ready.
1. Since you mentioned that this is your own form class, create a flag that tells your form that it is rearranging or not. Then override the Paint procedure of the form and if the rearranging flag is true don't allow the repainting and then once you are done rearranging call the refresh routine of the form so that if forces a repaint, otherwise just let the Paint procedure do its thing.
2. Whenever you need to rearrange items on a screen, have a panel or "Frame" that is not visible rearrange the components and then you can update the visible form with the new arrangement.
@mikelittlewood:
I have to rearrange the controls after the create and an enabled + doblebuffering doesn't make it much better.
@kretzschmar:
This works fine (replace onFormShow with OnShow).
@radikalQ3:
The idea is great - but I have the problem that the form does not want to refresh totally.
An invalidate of the form does not help.
It seems so whether I have to go through all the controls of the form and invalidate them all separately. But this cannot be the solution. Certainly I am only too blind to see the easiest solution.
Could you possibly put all the controls in your form onto a client-aligned panel, and set the panel's visible to false before rearranging?
That way the form's events are not involved, and if you put a pretty picture (or a snapshot of the form before you rearrange it) on another panel behind the first one, it'll keep the user happy while he waits.
If you want to rearrange before the form is shown, have you tried the onLoaded event ?
Chris
Business Accounts
Answer for Membership
by: mikelittlewoodPosted on 2005-08-31 at 07:07:35ID: 14793857
Should you not rearrange the components on the create of the form?
Are you just having problems with the form flickering? Would disabling the form and setting the doublebuffered property of the form the TRUE help?