Why can't I pass a variable to Model's constructor in Code Igniter?

Question

It seems that it is impossible to pass a variable to a Model's Constructor in Code Igniter. Maybe I'm missing something in MVC or Code Igniter, but I don't understand what.

In my case, should I use librairies instead of Model ? (librairies actually accept parameters)

Actually my code is looking like this, and I think it's a bit strange :

Controller :

class User extends CI_Controller {
    public function user($user_id) {
        $this->load->model('user');
        $this->user->setId($user_id);

        $data['username'] = $this->user->getName();     
        // Isn't it a bit strange ? I can load the class User even if the User doesn't mean anything ?
    }
}

Model :

class User extends CI_Model {
    private $id;
    private $name;

    public function setId($id) {
        $this->id = $id;
        // Retrieve data from DB...
        $this->name = $retrieved_data['name'];
    }

    public function getName() {
        return $this->name;
    }
}

Answer 1

Try this:

Controller:

class User extends CI_Controller {

    public function user($user_id) {
        $this->load->model('user_model');

        $data['username'] = $this->user_model->getName($user_id);     
    }
}

Model:

class User_model extends CI_Model {

    public function getName($user_id) {
        //Retrieve data from DB using the $user_id variable...
        return $retrieved_data['name'];
    }
}

Seems like a more logical and faster way to do it. Not sure if it complies with the rest of your code, but it might help you track down the errors.