Yii使用Captcha验证码的方法

class UserLogin extends CFormModel
{
 public $username;
 public $password;
 public $rememberMe;
 public $verifyCode;
 public function rules()
 {
  return array(
   // username and password are required
   array('username, password,verifyCode', 'required'),
   // rememberMe needs to be a boolean
   array('rememberMe', 'boolean'),
   // password needs to be authenticated
   array('password', 'authenticate'),
   // verifyCode needs to be entered correctly
   array('verifyCode', 'captcha', 'allowEmpty'=>!CCaptcha::checkRequirements()),
  );
 }
 /
   Declares attribute labels.
  /
 public function attributeLabels()
 {
  return array(
   'rememberMe'=>Yii::t('user',"Remember me next time"),
   'username'=>Yii::t('user',"username or email"),
   'password'=>Yii::t('user',"password"),
   'verifyCode'=>Yii::t('user','Verification Code'),
  );
 }
}

public function actions()
{
 return array(
  // captcha action renders the CAPTCHA image displayed on the contact page
  'captcha'=>array(
   'class'=>'CCaptchaAction',
   'backColor'=>0xf4f4f4,
   'padding'=>0,
   'height'=>30,
   'maxLength'=>4,
  ),
  );
}
ublic function actionLogin()
{
 if (Yii::app()->user->isGuest) {
  $model=new UserLogin;
  // collect user input data
  if(isset($_POST['UserLogin']))
  {
   $model->attributes=$_POST['UserLogin'];
//在此核对验证码
   if($this->createAction('captcha')->validate($model->verifyCode, false))
   {
    // validate user input and redirect to previous page if valid
    if($model->validate()) {
    //admin login only
    if( Yii::app()->getModule('user')->isAdmin()==1 )
    {
    $this->lastViset();
    if (strpos(Yii::app()->user->returnUrl,'/index.php')!==false)
     $this->redirect(Yii::app()->controller->module->returnUrl);
    else
     $this->redirect(Yii::app()->user->returnUrl);
    }else
    {//if no admin when login out
     $this->redirect(Yii::app()->controller->module->logoutUrl);
    }
   }
   }else
   {//提示错误
    $model->addError('verifyCode','验证码不对');
   }
  }
  // display the login form
  $this->render('/user/login',array('model'=>$model));
 } else
  $this->redirect(Yii::app()->controller->module->returnUrl);
}

if($this->createAction('captcha')->validate($model->verifyCode, false))
{

<?php $this->widget('CCaptcha'); ?>
  <?php echo CHtml::activeTextField($model,'verifyCode',array('tabindex'=>1)); ?>
<img src="http://.XXXX./uploads/123456.jpg" alt="">