为else子句的foreach()提供的无效参数 - Invalid argument supplied for foreach() on else clause

Invalid argument supplied for foreach() on else clause

本文关键字：无效参数 else 子句 foreach | 更新日期: 2023-09-27

我正试图从数据库中获取记录，并单击一个链接，它传递参数以获取所需的url。但是当我点击链接时，我得到以下错误:

警告:第31行/home/next/public_html/cms/index.php中foreach()的参数无效

使用的代码是:

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', '1');
    require_once('includes/class-query.php');
    if ( !empty ( $_GET ) ) {
        if ( !empty ( $_GET['p'] ) ) {
            $post = $_GET['p'];
        }
        if ( !empty ( $_GET['cat'] ) ) {
            $cat = $_GET['cat'];
        }
    }
    if ( empty ( $post ) && empty ( $cat ) ) {
        $posts_array = $query->all_posts();
    } elseif ( !empty ( $post ) ) {
        $posts_array = $query->post($post);
    } elseif ( !empty ( $cat ) ) {
        echo 'cat';
    } ?>
<html>
    <head>
        <title></title>
    </head>
    <body>
        <?php foreach ( $posts_array as $post ) : ?>
            <div class="post">
                <h1><a href="?p=<?php echo $post->ID; ?>"><?php echo $post->post_title; ?></a></h1>
                <p><?php echo $post->post_content; ?></p>
            </div>
        <?php endforeach; ?>
    </body>
</html>

这段代码的失败情况是定义了$cat。再加上@Mohammad Imran Ashraf的建议，如果你写这样的东西，错误就会消失。

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', '1');
    require_once('includes/class-query.php');
    if ( !empty ( $_GET ) ) {
        if ( !empty ( $_GET['p'] ) ) {
            $post = $_GET['p'];
        }
        if ( !empty ( $_GET['cat'] ) ) {
            $cat = $_GET['cat'];
        }
    }
    if ( empty ( $post ) && empty ( $cat ) ) {
        $posts_array = $query->all_posts();
    } elseif ( !empty ( $post ) ) {
        $posts_array = $query->post($post);
    } elseif ( !empty ( $cat ) ) {
        $posts_array = array();
    } ?>
<html>
    <head>
        <title></title>
    </head>
    <body>
        <?php foreach ( $posts_array as $post ) : ?>
            <div class="post">
                <h1><a href="?p=<?php echo $post->ID; ?>"><?php echo $post->post_title; ?></a></h1>
                <p><?php echo $post->post_content; ?></p>
            </div>
        <?php endforeach; ?>
    </body>
</html>

或

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', '1');
    require_once('includes/class-query.php');
    if ( !empty ( $_GET ) ) {
        if ( !empty ( $_GET['p'] ) ) {
            $post = $_GET['p'];
        }
        if ( !empty ( $_GET['cat'] ) ) {
            $cat = $_GET['cat'];
        }
    }
    $posts_array = array();
    if ( empty ( $post ) && empty ( $cat ) ) {
        $posts_array = $query->all_posts();
    } elseif ( !empty ( $post ) ) {
        $posts_array = $query->post($post);
    } elseif ( !empty ( $cat ) ) {
        echo "cat";
    } ?>
<html>
    <head>
        <title></title>
    </head>
    <body>
        <?php foreach ( $posts_array as $post ) : ?>
            <div class="post">
                <h1><a href="?p=<?php echo $post->ID; ?>"><?php echo $post->post_title; ?></a></h1>
                <p><?php echo $post->post_content; ?></p>
            </div>
        <?php endforeach; ?>
    </body>
</html>

这两种解决方案中的任何一种都可以。希望能有所帮助。根本原因是未初始化的阵列$posts_array。因此，要么首先初始化它，要么在else子句中为它赋值。

您需要在最后一个else中传递一个数组，因为您在另外两个if中返回一个数组，并且使用该数组进行foreach循环。

修改此代码

if ( empty ( $post ) && empty ( $cat ) ) {
        $posts_array = $query->all_posts();
    } elseif ( !empty ( $post ) ) {
        $posts_array = $query->post($post);
    } elseif ( !empty ( $cat ) ) {
     //Change this line and pass an array instead of echo something
        echo 'cat';
    }