[Lazarus] Dynamic creation of TTrackBar

[Brad Campbell]

Duncan Parsons wrote:
> Not got Laz/fpc code near me, but my guess is that when you have a
> TTrackBar on the form, the unit that it's housed in will be added to the
> uses list, and if you delete it (provided no other referenced classes
> are included) it may get removed.
> 
> Find which unit TTrackBar is declared in and add it to the relevant uses
> clause by hand..
> 
> Does that help?

No, not really. I had already thought along the same lines and checked it out.

I would have thought that given I'm referencing TTrackBar in the array definition it would grumble 
if the unit was not in the uses clause anyway.

Thanks for the thought tho. I've certainly been caught by errors like this in the past.

For reference, here is the complete procedure.
The form var section has this :

Var
   TapSliders : Array[0..15] of TTrackBar;
   TapLabels : Array[0..15] of TLabel;

This is where I create some of the sliders.

Any suggestions on how I can de-crapify this process is most welcome too :) I'm creating an array of 
sliders at run time which are all aligned against each other on a panel in 2 rows. I've fixed the 
numbers for testing purposes, but it has / will been / be dynamic depending on the hardware it is 
talking to.


procedure TForm1.FormCreate(Sender: TObject);
Var
         I : Integer;
begin
   Ser := TBlockSerial.Create;
   For I := 0 to 15 do
       Begin
       TapLabels[I] := TLabel.Create(Panel2);
       TapLabels[I].Layout := tlCenter;
       TapLabels[I].Alignment := taCenter;
       TapLabels[I].Parent := Panel2;
       TapLabels[I].Caption := 'L'+IntToStr(I);
       TapLabels[I].Anchors := [];
       End;

   For I := 0 to 15 do
       Begin
       TapSliders[I] := TTrackBar.Create(Panel2);
       TapSliders[I].Top := 1;
       TapSliders[I].Max := 32768;
       TapSliders[I].Position:= I*50;
       TapSliders[I].Name := 'TapSliders'+IntToStr(I);
       TapSliders[I].Parent := Panel2;
       TapSliders[I].Orientation := trVertical;
       TapSliders[I].TickStyle := tsNone;
       TapSliders[I].OnChange:= @TrackBar1Change;
       TapSliders[I].Tag := I+$ABCD;
       TapSliders[I].BorderSpacing.Left := 10;
       TapSliders[I].Width := TapSliders[I].Width + 5;
       End;

       For I := 0 to 7 do
           Begin
           TapSliders[I].AnchorSide[akTop].Control := Panel2;
           TapSliders[I].AnchorSide[akTop].Side := asrTop;
           TapSliders[I].Height := (Panel2.Height Div 2) - 5 - TapLabels[0].Height;
           TapLabels[I].AnchorSide[akTop].Control := TapSliders[I];
           TapLabels[I].AnchorSide[akTop].Side := asrBottom;
           TapLabels[I].AnchorSide[akLeft].Control := TapSliders[I];
           TapLabels[I].AnchorSide[akLeft].Side := asrLeft;
           TapLabels[I].AnchorSide[akRight].Control := TapSliders[I];
           TapLabels[I].AnchorSide[akRight].Side := asrRight;
           TapLabels[I].Anchors := TapLabels[I].Anchors+[akTop,akLeft,akRight];
           End;

       For I := 8 to 15 do
           Begin
           TapSliders[I].AnchorSide[akTop].Control := TapLabels[I-8];
           TapSliders[I].AnchorSide[akTop].Side := asrBottom;
           TapSliders[I].AnchorSide[akBottom].Control := TapLabels[I];
           TapSliders[I].AnchorSide[akBottom].Side := asrtop;
           TapSliders[I].Anchors := TapSliders[I].Anchors+[akBottom];

           TapLabels[I].AnchorSide[akBottom].Control := Panel2;
           TapLabels[I].AnchorSide[akBottom].Side := asrBottom;
           TapLabels[I].AnchorSide[akLeft].Control := TapSliders[I];
           TapLabels[I].AnchorSide[akLeft].Side := asrLeft;
           TapLabels[I].AnchorSide[akRight].Control := TapSliders[I];
           TapLabels[I].AnchorSide[akRight].Side := asrRight;
           TapLabels[I].Anchors := TapLabels[I].Anchors+[akBottom,akLeft,akRight];
           End;

       TapSliders[0].AnchorSide[akLeft].Control := Panel2;
       TapSliders[0].AnchorSide[akLeft].Side := asrLeft;

       TapSliders[8].AnchorSide[akLeft].Control := Panel2;
       TapSliders[8].AnchorSide[akLeft].Side := asrLeft;

       For I := 1 to 7 do
           Begin
           TapSliders[I].AnchorSide[akLeft].Control := TapSliders[I-1];
           TapSliders[I+8].AnchorSide[akLeft].Control := TapSliders[I-1+8];
           TapSliders[I].AnchorSide[akLeft].Side := asrRight;
           TapSliders[I+8].AnchorSide[akLeft].Side := asrRight;
           End;
       For I := 0 to 15 do
           TapSliders[I].Anchors := TapSliders[I].Anchors+[akTop,akLeft];
end;

Regards,
Brad
-- 
Dolphins are so intelligent that within a few weeks they can
train Americans to stand at the edge of the pool and throw them
fish.