TText, TGridLayout の BeginUpdate / EndUpdate 利用

Unit2.pas

uses
  System.Generics.Collections;

type
  TOpenText = class(TText);

procedure TForm1.CreateRandomText;
var
  x, y: Integer;
  Text: TText;
  Texts: TList<TText>;
begin
  Texts := TList<TText>.Create;
  try
    GridLayout1.BeginUpdate;
    try
      for y := 0 to Trunc(GridLayout1.Height / GridLayout1.ItemHeight) do
        for x := 0 to Trunc(GridLayout1.Width / GridLayout1.ItemWidth) do
        begin
          Text := TText.Create(Self);
          Texts.Add(Text);

          TOpenText(Text).Layout.BeginUpdate;

          Text.Text := Chr(Ord('A') + Random(25));
          GridLayout1.AddObject(Text);
        end;

      for Text in Texts do
        TOpenText(Text).Layout.EndUpdate;
    finally
      GridLayout1.EndUpdate;
    end;
  finally
    Texts.DisposeOf;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  CreateRandomText;
end;

procedure TForm1.FormResize(Sender: TObject);
begin
  CreateRandomText;
end;

end.