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

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

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