php - 需要帮忙！将其他商品添加到购物车时出错

Question

我正在为我的第一辆 php 购物车而苦苦挣扎。我有一个 php 文件来将项目添加到购物车会话。addcart.php

<?php
include 'dbconnect.php';
session_start();
$id= $_GET['id'];

if(!is_null($id)){
if(isset($_SESSION['cart']) && count($_SESSION['cart']) > 0){

    // increment product quantity if already exists
    // or create a new one
    add_or_increment_product_to_cart($id, $_SESSION['cart']);

} else {
    // initialize cart
    // add the first product
    $_SESSION['cart'] = array();
    array_push($_SESSION['cart'], (object) array('id' => $id, 'quantity' => 1));
}
}

function add_or_increment_product_to_cart($id, $cart){

foreach ($cart as $key => $product) {
    if($id == $product->id){
        $product->quantity++;
        return;
    }
}

array_push($_SESSION['cart'], (object) array('id' => $id, 'quantity' => $product));
}

header('location:cart.php');
?>

我有一个 php 页面来显示购物车会话中的所有项目。如果我只是将一件商品添加到购物车中，它就可以正常工作。

购物车.php

<?php 

$page_title = "Cart";
include_once ('header.html'); //include session_start() and others things
include ('dbconnect.php');
if($_SESSION['login']==null)
{
header ("location:login.php");
}
?>

<div id="content">
<table border="1">
<form action="update_cart.php" method="post">
<?php
$total_price=0;
if(isset($_SESSION['cart']) ? $_SESSION['cart'] : null)
{
echo "<tr>
    <th></th>
    <th>Product</th>
    <th>Price</th>
    <th>Quantity</th>
    </tr>";
foreach ($_SESSION['cart'] as $key => $product) {
    $the_query = "SELECT * FROM products WHERE id=" . $product->id." LIMIT 1";
    $the_product = $db->query($the_query) or die('Query failed: ' .  mysql_error());
        $the_product->execute();
        $the_product->setFetchMode(PDO::FETCH_OBJ);

        while ($row = $the_product->fetch()){

        echo "<tr><td>";
        echo "<img src='".$row->image_url_small."' /></a></td>";
        echo "<td><strong>".$row->name."</strong></td><td><em>$".$row->price."</em>";
        echo '</td>';
        echo '<td><input type="text" name="'.$row->id.'" class="override" value="'.$product->quantity.'"/></td>';
        //echo '<td><a href="update_cart.php?id='.$row->id.'&quantity='.$product->quantity.'">Update</a></td>';
        echo '<td><a href="do_deletecart.php?id='.$row->id.'">Delete item </a></td></tr>';
        $total_price = $total_price + $row->price*$product->quantity;
    }}

    echo "<tr><td colspan='2'></td></tr>";
    echo "<tr><td style='text-align:center;font-size:40px;'>$</td><td><strong>Total</strong><br /><em>$".$total_price."</em></td></tr>";
    $_SESSION['total']=$total_price;

}
 else {
echo "Your cart is empty.";
}
?>
<tr><td>
<!----<input type = "submit" value="Checkout"/></td>----->
<td><input type = "submit" value="Update"/></td></tr>

</form>
</table>
<br /><a href="empty_cart.php">Empty Cart</a> <a href="products.php">Show products</a><br /><br />
</div>
<?php 
include_once ('footer.html');
?>

修复此错误的任何建议“可捕获的致命错误：类 stdClass 的对象无法在第 37 行的 /home/s3393354/public_html/Assignment2/cart.php 中转换为字符串”。

echo '<td><input type="text" name="'.$row->id.'" class="override" value="'.$product->quantity.'"/></td>';

提前致谢。

Answer 1

在顶部cart.php没有。session_start();放在上面

<?php
session_start();