我的CI_Controller中的写上下文中不能使用函数返回值

Question

    <?php
    class Cart extends CI_Controller{

   public $paypal_data = '';
   public $tax;
   public $shipping;
   public $total =0;
   public $grand_total;

   //cart index
   public function index(){
    //load view
    $data('main_content') = 'cart';
    $this->load->view('layouts/main', $data);
   }//end function

   //add to Cart
   public function add(){
    //item data in a array construct
    $data = array('id'=> $this->input->post('item_number'), 'qty'=>   $this->input->post('qty'), 'price'=> $this->input->post('price'), 'name'=>  $this->input->post('title'));//end statement

   }//end function

}//end class cart

The above code causes error as follows:"Fatal error: Cant' use function return value in write context". I looked and searched many time at the above code but just can not seem to find the error. I would greatly appreciate it if someone can help.

Answer 1

The problem is this line:

$data('main_content') = 'cart';

Using parentheses means you're calling a function, but you can't assign to a function call. You probably meant to assign to an array index, but you have no $data array. I see you've created $data in the add() function, but that variable is local to that function. They probably both should be class properties, so they should be $this->data. And in index() you need to use square brackets.

   public function index(){
    //load view
    $this->data['main_content'] = 'cart';
    $this->load->view('layouts/main', $this->data);
   }//end function

   //add to Cart
   public function add(){
    //item data in a array construct
    $this->data = array('id'=> $this->input->post('item_number'), 'qty'=>   $this->input->post('qty'), 'price'=> $this->input->post('price'), 'name'=>  $this->input->post('title'));//end statement

   }//end function