thinkphp3.2.3中显示一个查询功能，在首页点击查询，结果出来，点击下一页为什么显示全部

//后台首页
public function index(){
$title = '首页';
$this->assign('title',$title);
$user = D('UserView');
//判断有没有点击搜索
if(isset($_POST['user_name'])){
$where = array(
'user_name' => array('LIKE','%'.I('post.user_name').'%'),
);
}else{
$where="1";
}
$search_name = $_POST['user_name'];
$this->assign('search_name',$search_name);
//实例化分页，进行数据显示
$count = $user->where($where)->count();
$page = new\Think\Page($count,2);
$page->setConfig('header', '

共%TOTAL_ROW%条记录 第%NOW_PAGE%页/共%TOTAL_PAGE%页');
$page->setConfig('prev', '上一页');
$page->setConfig('next', '下一页');
$page->setConfig('last', '末页');
$page->setConfig('first', '首页');
$page->setConfig('theme', '%FIRST%%UP_PAGE%%LINK_PAGE%%DOWN_PAGE%%END%%HEADER%');
$page->lastSuffix = false;//最后一页不显示为总页数
$show = $page->show();
$list = $user->where($where)->limit($page->firstRow,$page->listRows)->select();
$this->assign('list',$list);
$this->assign('page',$show);
$this->display();
$this->display();

}

代码写的比较乱，还请见谅， 请各位大神帮忙看看，谢谢

这种一般都是你在下一页链接哪里,没有传入搜索条件那个值造成的,要在链接后面传搜索的那个参数