不显示购物车中的产品

Question

<?php 
    error_reporting(E_ALL);
    ini_set('display_errors', '1');

    $name = isset($_GET['NameOfTheDVD']) ? ($_GET['NameOfTheDVD']): "";
      $DVDID = isset($_GET['DVDID']) ? ($_GET['DVDID']) : "";
      $Quantity =isset($_GET['Quantity']) ? ($_GET['Quantity']) : "";
    $action = isset($_GET['action']) ? $_GET['action'] : "";

    if($action=='removed'){
        echo "<div>" . $_GET['NameOfTheDVD'] . " was removed from cart.</div>";
    }

       if(isset($_SESSION['cart'])){
        $ids = " ";
        foreach($_SESSION['cart'] as $DVDID){

        }

        // remove the last comma
        $ids = rtrim($ids, ',');

        require "connect.php";

        $query = "SELECT DVDID, NameOfTheDVD, Quantity FROM DVD WHERE DVDID IN ({$ids})";
        $stmt = $dbhandle->prepare( $query );
        $stmt->execute();

        $num = $stmt->rowCount();

        if($num>0){
            echo "<table border='0'>";//start table

                // our table heading
                echo "<tr>";
                    echo "<th class='textAlignLeft'>Product Name</th>";
                    echo "<th>Quantity</th>";
                    echo "<th>Action</th>";
                echo "</tr>";

                //also compute for total price
                $totalQuantity = 0;

                while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
                    extract($row);

                    $totalQuantity += $Quantity;

                    //creating new table row per record
                    echo "<tr>";
                        echo "<td>{$name}</td>";
                        echo "<td class='textAlignRight'>{$Quantity}</td>";
                        echo "<td class='textAlignCenter'>";
                            echo "<a href='RemoveFromCart.php?DVDID={$DVDID}&name={$name}' class='customButton'>";
                                echo "<img src='images/remove-from-cart.png' title='Remove from cart' />";
                            echo "</a>";
                        echo "</td>";
                    echo "</tr>";
                }

                echo "<tr>";
                    echo "<th class='textAlignCenter'>Total Price</th>";
                    echo "<th class='textAlignRight'>{$totalQuantity}</th>";
                    echo "<th></th>";
                echo "</tr>";

            echo "</table>";
            echo "<br /><div><a href='#' class='customButton'>Checkout</a></div>";
        }else{
            echo "<div>No products found in your cart. :(</div>";
        }

    }else{
        echo "<div>No products in cart yet.</div>";
    }
    ?>

这是产品要显示但不显示的地方。我不知道问题是什么。我不知道是否应该有一些if语句检查如果不显示结果会话是否为空。 Stack溢出有2个与此相关的主题，但我认为它们没有得到解决。

这是我的AddtoCart.php

<?php
   session_start();

   // get the product id
   $DVDID = isset($_GET['DVDID']) ? $_GET['DVDID'] : "";
   $name = isset($_GET['NameOfTheDVD']) ? $_GET['NameOfTheDVD'] : "";

   /* 
    * check if the 'cart' session array was created
    * if it is NOT, create the 'cart' session array
 . */
   if(!isset($_SESSION['cart'])){
     $_SESSION['cart'] = array();
    }

   // check if the item is in the array, if it is, do not add
   if(in_array($DVDID, $_SESSION['cart'])){
      // redirect to product list and tell the user it was added to cart
      header('Location: shop.php?action=exists&DVDID' . $DVDID . '&name=' . $name);
    }

     // else, add the item to the array
    else{
    array_push($_SESSION['cart'], $DVDID);

    // redirect to product list and tell the user it was added to cart
    header('Location: shop.php?action=add&DVDID' . $DVDID . '&name=' . $name);
    }

?>

感谢您提供的任何帮助