Normally, adding text to a memo control scrolls the memo to the bottom of the inserted text. To prevent that, call Lines.BeginUpdate
before adding text, and call EndUpdate
afterwards:
procedure TForm1.Button1Click(Sender: TObject);
begin
Memo1.Lines.BeginUpdate;
try
Memo1.Lines.Add('...');
Memo1.Lines.Add('...');
...
finally
Memo1.Lines.EndUpdate;
end;
end;