delphi 高亮选中MEMO某一行

http://www.delphitop.com/html/kongjian/2641.html
选中第5行

//转到指定行并选中这行的文本
procedure SelectLine(Memo1: TMemo; ln: Integer);
begin
  Memo1.SelStart := SendMessage(Memo1.Handle, EM_LINEINDEX, ln - , );
  Memo1.SelLength := Length(Memo1.Lines[ln - ]);
end;

http://www.52delphi.com/list.asp?ID=570