Creating Controls in a TScrollBox at Runtime Starts to ReOrder

Question

I'm using Delphi 10.1 and Firemonkey and looking to add controls to a TScrollBox at Runtime and have come across some strange behaviors.

For this example I create Labels and add them to a TScroll box.

The Label is set as TAlignLayout.Top so I assume every new Label created will sit below the previous.

• First Label that gets created goes to the top.
• Second Label that gets created goes below the first.
• Third Label that gets created goes between the first and second Label.
• Any more Labels that created then stacks under the First Label.

I want the Labels to be created from top down in order of creation. Any ideas what I've done wrong?

This is the code to create the Labels:-

procedure TForm1.Button4Click(Sender: TObject);
var
  lbFileDate: TLabel;
begin
  ScrollBox2.BeginUpdate;
  lbFileDate := TLabel.Create(ScrollBox2);
  lbFileDate.Parent := ScrollBox2;
  lbFileDate.Align := TAlignLayout.Top;
  lbFileDate.Text := DateTimeToStr(Now);
  ScrollBox2.EndUpdate;
end;

I've done something very similar in Delphi 10.1 VCL and the creation process works by always putting the last Label to the top.

tia

Answer 1

Looks like for already laid out controls any additional controls go to where they can be squeezed in based on their coordinates which default to 0,0. You can give a new control a large y so it starts under the rest. Before they are laid out like inside a begin/end update block they can be placed on top of each other and will get laid out based on creation order.

procedure TForm1.Button1Click(Sender: TObject);
var
  lbFileDate: TLabel;
begin
  ScrollBox2.BeginUpdate;
  for var I : integer := 1 to 10 do
  begin
    lbFileDate := TLabel.Create(ScrollBox2);
    lbFileDate.Parent := ScrollBox2;
    lbFileDate.Position.Y := 1E10;
    lbFileDate.Align := TAlignLayout.Top;
    lbFileDate.Text := DateTimeToStr(Now) + ' ' + IntToStr(I);
  end;
  ScrollBox2.EndUpdate;
end;