Loop Through Components
lazarus / 10-Designer

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rjmatm · 2005-06-09 18:36

I have 5 TImage components on a form. 

myImg1
myImg2
myImg3
myImg4
myImg5

I would like to run a for loop to do some things with them in the code
much like what can be done with an array.

for i := 1 to 5 do
  begin
  myArray := 20;
  end;

Is there a way to set up those image components so they can be used
like that?

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matthijs · 2005-06-10 15:04

Yes. In the form definition add something like:
Code: [Select]
  TForm1 = class(TForm)
    procedure Form1Create(Sender: TObject);
    procedure Form1Destroy(Sender: TObject);
  private
    { private declarations }
    ImageArray: Array[1..5] of TImage;
  public
    { public declarations }
  end;

And make the create and destroy events as follows:
Code: [Select]
procedure TForm1.Form1Create(Sender: TObject);
var
  I: Integer;
begin
  for I := 1 to 5 do begin
    ImageArray[I] := TImage.Create(nil);
    // Set Properties of the Image
  end;
end;

procedure TForm1.Form1Destroy(Sender: TObject);
var
  I: Integer;
begin
  for I := 1 to 5 do
    ImageArray[I].Free;
end;

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Marc · 2005-06-13 12:03

If you Creqate the images with the form as owner ( ImageArray :=
TImage.Create(Self) )  you don't even have to frre them in your
Destroy

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rjmatm · 2005-06-13 17:07

I tried the first example.  There were no errors at all, however, the
images would not show on the form.

I'll try setting the owner to Self and see what happens.

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matthijs · 2005-06-13 17:17

You have to set the parent as well. No need to set the owner, as long
as you remember to free them on destroy.  (Althought Marc is right, if
you set the owner you don't need to bother to free them yourself. But
I like it the hard way, what you create yourself you destroy yourself
as well.)

Code: [Select]
ImageArray[I].Parent := Self;

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rjmatm · 2005-06-14 02:22

WOW! Thanks for the help guys!  It works great!

Just to show everyone how it came together here is the code that I
used that's working.

Code: [Select]
  TForm1 = class(TForm)
  procedure Form1Create(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
    ImageArray: Array [1..5] of TImage;

  end;

var
  Form1: TForm1;

implementation


Code: [Select]
procedure TForm1.Form1Create(Sender: TObject);
var
i: Integer;
begin

  for i := 1 to 5 do
    begin
    ImageArray[i] := TImage.Create(Self);
    ImageArray[i].Parent := Self;
    // Set any other properties etc.
   end;

end;