这个问题在这里已经有答案了：
使用php的“notice:未定义变量”、“notice:未定义索引”和“notice:未定义偏移量”（28个答案）
两年前关门了。
我刚开始学习php，这是我的第一个项目，它是创建一个包含各种表的数据库。我在这里遇到的问题是，当页面打印出来时，我似乎无法编辑现有的产品
注意：未定义的变量：c:\xampp\htdocs\goodsdept\u manager\edit\u product.php第15行中的product\u id
这是我的密码：
编辑\u product.php
<?php
$category_id = $_POST['category_id'];
$code = $_POST['code'];
$name = $_POST['name'];
$price = $_POST['price'];
// $product_id = $_POST['productID'];
if(isset($_POST['productID'])){ $product_id = $_POST['productID']; }
if(empty($code) || empty($name) || empty($price)){
$error = "Invalid product data.";
include('error.php');
} else{
require_once('database.php');
$query = "UPDATE products SET categoryID = '$category_id', productCode = '$code', productName = '$name', listPrice = '$price' WHERE productID = '$product_id'";
$statement = $db->prepare($query);
$statement->execute();
$statement->closeCursor();
include('index.php');
}
?>编辑\u product\u form.php
<?php
$product_id = $_POST['product_id'];
//Get the categories for the pull down menu
require_once('database.php');
$query = "SELECT*FROM categories ORDER BY categoryID";
$categories = $db->query($query);
$query = "SELECT*FROM products WHERE productID = $product_id";
$edit_product = $db->query($query);
$edit_product = $edit_product->fetch();
//Define the VALUES
$code = $edit_product['productCode'];
$name = $edit_product['productName'];
$price = $edit_product['listPrice'];
$category_id = $edit_product['categoryID'];
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
<link rel="stylesheet" type="text/css" href="main.css" />
</head>
<body>
<h1>Product Manager</h1>
<h1>Edit Product</h1>
Product ID: <?php echo $product_id; ?><br />
code: <?php echo $code; ?>
<form action="edit_product.php" method="post"
id="edit_product_form">
<label>Category:</label>
<select name="category_id">
<?php foreach ($categories as $category) : ?>
<option value="<?php echo $category['categoryID']; ?>">
<?php echo $category['categoryName']; ?>
</option>
<?php endforeach; ?>
</select><br>
<label>Code:</label>
<input name="code" type="input" value="<?php echo $code; ?>"><br>
<label>Name:</label>
<input name="name" type="input" value="<?php echo $name; ?>"><br>
<label>List Price:</label>
<input name="price" type="input" value="<?php echo $price; ?>"><br>
<label> </label>
<input type="submit" value="Edit Product"/><br>
</form>
<footer>
<p>© <?php echo date("Y"); ?> The Goods Dept, Inc.</p>
</footer>
</body>
</html>以及index.php
<?php
require_once('database.php'); //calls the database.php file to validate the user
//Get Category ID
if (!isset($category_id)) {
$category_id = filter_input(INPUT_GET, 'category_id', FILTER_VALIDATE_INT);
if ($category_id == NULL || $category_id == FALSE) {
$category_id = 1;
}
}
//Get name for selected category
$queryCategory = 'SELECT * FROM categories
WHERE categoryID = :category_id';
$statement1 = $db->prepare($queryCategory);
$statement1->bindValue(':category_id', $category_id);
$statement1->execute();
$category = $statement1->fetch();
$category_name = $category['categoryName'];
$statement1->closeCursor();
// Get all categories
$query = 'SELECT * FROM categories
ORDER BY categoryID';
$statement = $db->prepare($query);
$statement->execute();
$categories = $statement->fetchAll();
$statement->closeCursor();
// Get products for selected category
$queryProducts = 'SELECT * FROM products
WHERE categoryID = :category_id
ORDER BY productID';
$statement3 = $db->prepare($queryProducts);
$statement3->bindValue(':category_id', $category_id);
$statement3->execute();
$products = $statement3->fetchAll();
$statement3->closeCursor();
?>
<!DOCTYPE html>
<html>
<!-- the head section -->
<head>
<title>The Goods Dept</title>
<link rel="stylesheet" type="text/css" href="main.css" />
</head>
<!-- the body section -->
<body>
<header><h1>Product Manager</h1></header>
<main>
<h1>Product List</h1>
<aside>
<!-- display a list of categories -->
<h2>Categories</h2>
<nav>
<ul>
<?php foreach ($categories as $category) : ?>
<li><a href=".?category_id=<?php echo $category['categoryID']; ?>">
<?php echo $category['categoryName']; ?>
</a>
</li>
<?php endforeach; ?>
</ul>
</nav>
</aside>
<section>
<!-- display a table of products -->
<h2><?php echo $category_name; ?></h2>
<table>
<tr>
<th>Code</th>
<th>Name</th>
<th class="right">Price</th>
<th> </th>
</tr>
<?php foreach ($products as $product) : ?>
<tr>
<td><?php echo $product['productCode']; ?></td>
<td><?php echo $product['productName']; ?></td>
<td class="right"><?php echo $product['listPrice']; ?></td>
<!-- Delete product -->
<td><form action="delete_product.php" method="post">
<input type="hidden" name="product_id"
value="<?php echo $product['productID']; ?>">
<input type="hidden" name="category_id"
value="<?php echo $product['categoryID']; ?>">
<input type="submit" value="Delete">
</form></td>
<!-- Update product -->
<td><form action="edit_product_form.php" method="post" id="edit_product_form">
<input type="hidden" name="product_id"
value="<?php echo $product['productID']; ?>">
<input type="hidden" name="category_id"
value="<?php echo $product['categoryID']; ?>">
<input type="submit" value="Edit">
</form></td>
</tr>
<?php endforeach; ?>
</table>
<p><a href="add_product_form.php">Add Product</a></p>
<p><a href="category_list.php">List Categories</a></p>
</section>
</main>
<footer>
<p>© <?php echo date("Y"); ?> The Goods Dept</p>
</footer>
</body>
</html>我自己一直在努力解决这个问题，所以我发现stackoverflow的Maven可以帮我。抱歉，如果愚蠢的错误，因为我仍然在学习，并一直期待提高。谢谢！
2条答案
按热度按时间rta7y2nd1#
根据你的错误信息，
$product_id未在您的范围内定义$query声明。因此，当在第15行中准备查询时，它是未定义的。要解决这个问题，只需替换
// $product_id = $_POST['productID'];与$product_id = "";初始化它。然后它将替换为if声明。否则，它将默认为空字符串。因此，$product\ id的值总是定义为空字符串，即使product_idpost请求中的字段无效。另一个选择是初始化
$product_id带null($product_id = NULL;)8i9zcol22#
你只是在设置
$product_id在edit_product.php如果你把它当作POST变量：…但你不是在传递表格
name的productID转到本页。您正确地将产品id传递给
edit_product_form.php通过一个name的productID在index.php，虽然你没有通过新的$product_id声明于edit_product_form.php至edit_product.php. 要更正此问题，您需要添加：到你的表格上
edit_product_form.php: