学步园

procedure TForm1.Button1Click(Sender: TObject);
var
  node: ttreenode;
  i: integer;
begin
  i := 0;
  node := treeview1.Items.GetFirstNode;
  while node <> nil do
  begin
    inc(i);
    node := node.GetNext;
  end;
  caption := inttostr(i);
end;