Mega Code Archive
Implement AfterShow, AfterCreate events
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Title: implement AfterShow, AfterCreate events?
{
Question/Abstract:
I often want to automatically run some code directly after the form has
shown. If this is done in the OnShow event it gets done while the form is
still invisible (not good if the code takes a little while to run.)
Currently, I use a Timer with its interval property set to about 200 and
enabled set to false. In the OnShow event I set Timer.Enabled := True and
the first statement in the OnTimer event is Timer.Enabled := False so the
event only runs once.
Answer:
Post a custom message to yourself.
The following code shows how to trigger a AfterShow, AfterCreate event.
}
const
WM_AFTER_SHOW = WM_USER + 300; // custom message
WM_AFTER_CREATE = WM_USER + 301; // custom message
type
TForm1 = class(TForm)
// OnShow event
procedure FormShow(Sender: TObject);
// OnCreate event
procedure FormCreate(Sender: TObject);
private
procedure WmAfterShow(var Msg: TMessage); message WM_AFTER_SHOW;
procedure WmAfterCreate(var Msg: TMessage); message WM_AFTER_CREATE;
public
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.WmAfterShow(var Msg: TMessage);
begin
ShowMessage('WM_AFTER_SHOW received!');
end;
procedure TForm1.WmAfterCreate(var Msg: TMessage);
begin
ShowMessage('WM_AFTER_CREATE received!');
end;
procedure TForm1.FormShow(Sender: TObject);
begin
// Post the custom message WM_AFTER_SHOW to our form
PostMessage(Self.Handle, WM_AFTER_SHOW, 0, 0);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
// Post the custom message WM_AFTER_CREATE to our form
PostMessage(Self.Handle, WM_AFTER_CREATE, 0, 0);
end;
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