CodeIgniter输入库不起作用

Question

When I use $this->input->post('something'); in CodeIgniter while making Shopping cart, my data is not inserting in to the cart/session. I have autoload session, cart, database, input as well. But no receiving any data.

When I print_r($data) I got all data but when I put it in $this->cart->insert($data) no data comes in it.

How can I solve this problem. My code is here below:

View

<form action="<?=  site_url()?>product/add" method="post">
<input type="number" name="qty" min="1" max="99" required="required" />
<input type="hidden" name="id" value="<?= $value->proid;?>" />
<input type="hidden" name="price" value="<?= $value->price;?>" />
<input type="hidden" name="name" value="<?= $value->title;?>" />
<input type="submit" name="submit" value="Add to Cart" />
</form>

Controller

class Product extends CI_Controller{

    public function index(){
        $data['products'] = $this->product_model->get_all();
        $this->load->view('products',$data);
    }

    public function add(){

        $id = $this->input->post('id',TRUE);
        $qty = $this->input->post('qty',TRUE);
        $price = $this->input->post('price',TRUE);
        $name = $this->input->post('name',TRUE);

        $data = array(
            'id'      => $id,
            'qty'     => $qty,
            'price'   => $price,
            'name'    => $name
        );

        $this->cart->insert($data);

        redirect('product','refresh');

    }

}