使用S方法的时候出现这个报这个错，无法加载缓存类型:File
$pid=I("pid");
$id=I("id");
if(!$list = S("index_list")){

$cate=M("cate")->order("sort")->select();
$parent=M("cate")->where(array("id"=>$pid))->find();
$list["left"]=Category::getChildsMore($cate,"",$pid);
$list["title"]=Category::getParents($cate,$id);
S("index_list",$list,10);
}
$this->assign("id",$id);
$this->assign("list",$list);
$this->assign("parent",$parent);
$this->display();