关于用两个按钮使MEMO里内容翻页(50分)

希望能用两个按钮对MEMO实现“翻上”“翻下”的功能
谢谢

sendmessage(memo1.handle,wm_hscroll,sb_pageright,0);(后翻一页）
sendmessage(memo1.handle,em_linescroll,0,-makelong(5,0));（下移5行）
参考!

//翻下一页
procedure TForm1.Button2Click(Sender: TObject);
begin
sendmessage(memo1.handle,WM_VSCROLL,SB_PAGEDOWN,0);
end;
//翻上一页
procedure TForm1.Button3Click(Sender: TObject);
begin
sendmessage(memo1.handle,WM_VSCROLL,SB_PAGEUP,0);
end;