Limiter le nombre de lignes dans un TMemo

procedure TForm1.Memo1Change(Sender: TObject);
const
MaxLineCount = 5;
begin
if Memo1.Lines.Count > MaxLineCount then
Memo1.Perform(EM_UNDO, 0, 0);
Memo1.Perform(EM_EMPTYUNDOBUFFER, 0, 0);
end;