Throw an Exception, convert it to Flash Message and render a page

Do you mean perhaps something like that?

...
public function set($price)
{
    if($price > 100) {
        throw new \ValidationException('Invalid Price');
        $this->getDI()->getShared("flash")->notice("Invalid price");
    }
    $this->price = $price;
    return $this;
}

Add a try/catch in the controller:

try {
    $model->set(100);
} catch (\Exception $e) {
    $this->flash->error($e->getException());
}

This will bahave like a normal exception. The second line will not be executed because an exceptionwas raised before.

Do you mean perhaps something like that?

...
public function set($price)
{
   if($price > 100) {
      throw new \ValidationException('Invalid Price');
      $this->getDI()->getShared("flash")->notice("Invalid price");
  }
   $this->price = $price;
   return $this;
}

Sounds good, but not DRY. It's not good to put try/catch clock in every validation.

I may put catch block in main application try/catch:

try {
    # All Phalcon code 
    ...
    throw new \ValidationException('Invalide price value')
    ....
} catch (\Phalcon\Exception $e) {
    ...
} catch (\ValidationException $e) {
    DI::getDefault()->get('flash')->error($e->getException());
}

What do you think?

Add a try/catch in the controller:

try {
  $model->set(100);
} catch (\Exception $e) {
   $this->flash->error($e->getException());
}

any help with this problem? i have this code:

public function authAction() {
        $this->view->disable();
        if ($this->request->isPost() == true) {
            $this->request->getPost("user_name");
            $this->request->getPost("user_password");

            $o_user = \BtsUser::findFirst(array(
                        'userName = :userName: and password = :password:',
                        'bind' => array(
                            'userName' => $this->request->getPost("user_name"),
                            'password' => md5($this->request->getPost("user_password"))
                        )
            ));
            if ($o_user === false) {
                $this->flash->error("Incorrect credentials");
            } else {
                if (!$o_user->systemActive) {
                    throw new Exception("The system was deactivated.");
                }
                $this->session->set("user-name", "Michael");
                ...
            }
        }
    }

Something like that? help!