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Object events in Project Source.

Posted on 2001-06-29
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Last Modified: 2010-04-06
I've created a small application, purely in the Project Source, not using any forms.

How, within this same file, can I handle the OnTimer event of a timer created at runtime?

Thanks,

MoonCalf.
0
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Question by:MoonCalf
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8 Comments
 
LVL 9

Expert Comment

by:ITugay
ID: 6238445
Hi MoonCalf,
to keep your resources clean take a look at Windows API functions
SetTimer and KillTimer.

-----
Igor.
0
 
LVL 9

Expert Comment

by:ITugay
ID: 6238464


sample:

procedure SomeTimerEvent(H: hwnd; Msg, ID: Integer; Time: DWord); stdcall;
begin
  Form1.Caption := IntToStr(Time);
end;

var
  TimerID: Integer;

initialization
  TimerID := SetTimer(0, 1, 500, @SomeTimerEvent);
finalization
  KillTimer(0, TimerID);
end.

-----
Igor.
0
 
LVL 1

Author Comment

by:MoonCalf
ID: 6238475
This is purely an example.  If I know how to handle the OnTimer event of a TTimer, I can handle any of the events of other objects as well.

It's the idea of handling the events that I need to understand, not any specific ones.  Maybe a TTimer was a bad one to choose.

MoonCalf.
0
What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

 
LVL 9

Accepted Solution

by:
ITugay earned 100 total points
ID: 6238498
Ok,
then you can create an "empty" object to prvide an interface part for "object" method, something like this

type
  TDummyObject = class(TObject)
     procedure SomeEvent(Sender: TObject);
  end;



procedure TDummyObject.SomeEvent(Sender: TObject);
begin
  // do something
end;

var
  Dummy: TDummyObject;
....
  Dummy := TDummyObject.Create;
  Timer1.OnTimer := Dummy.SomeEvent;


-----
Igor.


PS: if you'd like to avoid of dummy object then let me know :-)

 


0
 
LVL 1

Author Comment

by:MoonCalf
ID: 6238501
I'll give it a go.

Thanks.
0
 
LVL 6

Expert Comment

by:edey
ID: 6238505
you could try something like this:

uses ... extctrls;

type
 TMyDummyObject = class(TObject)
 public
  procedure doTimer(Sender : TObject);//event handlers need to be methods
 end;

var
 dummy : TDummyObject;
 timer : TTimer;

procedure TDummyObject.doTimer(sender : TObject);
begin
 ...
end;

begin

 ...

 dummy : TDummyObject.create;
 timer := TTimer.create(some_parent_object);
 timer.onTimer := dummy.doTimer;

 ...

 timer.enabled := false;
 dummy.free;
end;

GL
Mike
0
 
LVL 1

Author Comment

by:MoonCalf
ID: 6238533
Thanks for the answer, but it took a bit of "rewording" to get it to work correctly.

MoonCalf.
0
 
LVL 9

Expert Comment

by:ITugay
ID: 6238709
hi MoonCalf,

this is the "bonus track" for grade "C".
No dummy objects, just not typesafe code.

var
  Timer: TTimer;

procedure OnTimer(Self, Sender: TObject); register;
begin
  // do something here
  // e.g.  Form1.Caption := IntToStr(GetTickCount);
end;

begin

  Timer := TTimer.Create(nil);
  pointer((@@Timer.OnTimer)^):= @OnTimer;
  Timer.Interval := 100;
 
  .....
  Timer.Free;
end.

Good wishes,
Igor.
0

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