怎样把TreeView滚动条移动到最顶或最底? 不可以用鼠标来操作! :),该如何解决

怎样把TreeView滚动条移动到最顶或最底? 不可以用鼠标来操作! :)
rt

[解决办法]
procedure TForm1.Button1Click(Sender: TObject);
begin
if TreeView1.Items.Count > 0 then
TreeView1.Items[TreeView1.Items.Count - 1].MakeVisible;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
if TreeView1.Items.Count > 0 then
TreeView1.Items[0].MakeVisible;
end;