(Solved)TUpDown KeyDown event

[morknot]

I would like to vary the Increment value, say from 1 to 5, of an UpDown component at runtime by pressing the Shift key. Unfortunately the TUpDown component does not have an OnKeyDown event.

 In the past (to my surprise) I managed to add an event to a component created at runtime which didn't have an OnMouseWheel event by including:

type
  progbar=Class(TJvSpecialProgress)
 published
 property OnMouseWheel;
 end;

but the equivalent doesn't work for TUpDown, also created at runtime.

Is there a similar and simple method for TUpDown or do I have to try and create a new component.

Thanks.






 

[LeP]

You can capture OnKeyDown event on control associate to UpDown component (Edit1 in example) and:

[EDIT]: changed var inline ... 

Code: Pascal  [Select][+][-]

1. procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word;
2.   Shift: TShiftState);
3. var p: TComponent;
4. begin
5.   if (ssCTRL in Shift) and (key = vk_F1) then   //<--- This will activated if "CTRL + F1" is pressed, change this whatever you want
6.     for p in self.GetControls([ceftAll]) do
7.       begin
8.         if p is TUpDown then
9.           if (P as TUpDown).Associate = Sender then
10.             begin
11.               (P as TUpDown).Increment := 5;
12.               ShowMessage('Done');
13.             end;
14.       end;
15. end;
16.  

I take it from my old program code (in Delphi) ... should be tested in Lazarus.

[morknot]

Thank you for your reply.

I have experimented a bit more and found that with the mouse cursor over the UpDown component and with it highlighted, it does not automatically seem to get Focus. By using SetFocus in the MouseEnter event..

type
  myupdown=Class(TUpDown)
    published
    property OnKeyDown;
    property OnKeyUp;
   end;     

then OnkeyDown and OnKeyUp events now fire.

[LeP]

Locking focus on a component during mouse movement (which can then move to other components during the movement) isn't a positive experience, I think, and it can lead to annoying side effects: the user is actually acting on a control they didn't expect because it changed without their knowledge.
Then, obviously, your changes will only work if the component is instantiated at runtime; otherwise, you should build a new component and install it in the Lazarus IDE.