yii1.1提交保存数据不验证模型 [ 1.1 版本 ]

今天修改yii 1.1开发的一个程序，发生了神奇的一幕，后台登陆的时候会验证模型，提示需要输入用户名和密码、验证码等，可是进入后台之后，所有的模块提交保存数据都不会提示验证model里设置的rules，假如修改的数据是不符合model里的规则，页面自动跳转到列表页面，但是数据不会修改。数据符合model里的rules规则，则会修改保存数据，并提示保存成功，请教如何修改。
model如下：
`
public function rules()
{

// NOTE: you should only define rules for those attributes that
// will receive user inputs.
return array(
	array('username', 'required'),
	array('status, role_id, created_at, updated_at', 'numerical', 'integerOnly'=>true),
	array('username, email, avatar', 'length', 'max'=>255),
	array('email', 'email'),
	array('auth_key', 'length', 'max'=>32),
    array('username, password, captcha', 'required', 'on'=>'login'),
    array('captcha', 'captcha', 'allowEmpty'=>!extension_loaded('gd'), 'on'=>'login'),
    array('username, password, rePassword', 'required', 'on'=>'rePassword'),
	array('password', 'compare', 'compareAttribute'=>'password'),
	// The following rule is used by search().
	// @todo Please remove those attributes that should not be searched.
	array('id, username, auth_key, password_hash, password_reset_token, email, avatar, status, created_at, updated_at', 'safe', 'on'=>'search'),
);

}
controller如下：
public function actionUpdate($id)
{

$model=$this->loadModel($id);

// Uncomment the following line if AJAX validation is needed
//$this->performAjaxValidation($model);

if(isset($_POST['AdminUser']))
{
	$model->attributes = $_POST['AdminUser'];

	if($model->validate() && $model->save())
        Yii::app()->user->setFlash('success', Yii::t('app', 'Update Success'));
		$this->redirect(array('index'));
}

$this->render('update',array(
	'model'=>$model,
));

}
`