关于用thinkphp会员登录的表单自动验证的有关问题

关于用thinkphp会员登录的表单自动验证的问题？
我的MemberAction代码是

class MemberAction extends Action{
    public function insert()
	{
	header('Content-Type:text/html; charset=utf-8');
        $Member   =   D('developers');
        if($Member->create()) {
            $result =   $Member->add();
            if($result) {
                $this->success('注册成功！');
            }else{
                $this->error('注册失败！');
            }
        }else{
            $this->error($Member->getError());
        }
    }
 }
?>

class 	MemberModel extends Model {
    
    protected $_validate    =   array(
	    array("username","require","用户名不能为空"),
		array('username','','帐号名称已经存在！',0,'unique',1),
		array("username","checkLength","用户名长度不符合要求",0,'callback'),
        array('name','require','名字必须'),
		array("password","require","密码不能为空"),
		array("password","checkLength","密码长度的要求是5~15位之间",0,'callback'),
		array('repassword','password','两次密码输入不一致',0,'confirm'),
        );
    
	 protected $_auto = array( 
        array('status', '1', self::MODEL_INSERT), 
        array('create_time', 'time', self::MODEL_INSERT, 'function'), 
    ); 
  
}
?>