致命错误：未捕获错误：调用未定义的方法stdClass :: count（）

Question

I got this error in products.php page

Fatal error: Uncaught Error: Call to undefined method stdClass::count() in C:\xampp\htdocs\shopCart avigation.php:29 Stack trace: #0 C:\xampp\htdocs\shopCart\layout_head.php(27): include() #1 C:\xampp\htdocs\shopCart\products.php(15): include('C:\xampp\htdocs...') #2 {main} thrown in C:\xampp\htdocs\shopCart avigation.php on line 29

This is the error part of navigation.php page. Last line is 29

// count products in cart
$cart_item = new \stdClass();
$cart_item->user_id=1; // default to user with ID "1" for now
$cart_count=$cart_item->count();

This is count function in cartItem class

class CartItem{

    // database connection and table name
    private $conn;
    private $table_name = "cart_items";

    // object properties
    public $id;
    public $product_id;
    public $quantity;
    public $user_id;
    public $created;
    public $modified;

    // constructor
    public function __construct($db){
        $this->conn = $db;
    }
    // count user's items in the cart
    public function count() {

            // query to count existing cart item
            $query = "SELECT count(*) FROM " . $this->table_name . " WHERE user_id=:user_id";

            // prepare query statement
            $stmt = $this->conn->prepare( $query );

            // sanitize
            $this->user_id=htmlspecialchars(strip_tags($this->user_id));

            // bind category id variable
            $stmt->bindParam(":user_id", $this->user_id);

            // execute query
            $stmt->execute();

            // get row value
            $rows = $stmt->fetch(PDO::FETCH_NUM);

            // return
            return $rows[0];
        }
}

how can i solve it?

Answer 1

You are instantiating $cart_item as a stdClass object. I am assuming from your code example and class it should be instantiated as a CartItem object, like so:

$cart_item = new CartItem($db);

You were getting the error because stdClass doesn't have a count() method.