如何验证复选框集/复选框数组？

Question

在互联网上寻找了多年之后，我想我想在这里寻求帮助。我这里有一个简单的复选框表，我在其中单击复选框，结果以 PHP 形式发回，但是当我不单击任何复选框并提交时，我收到以下错误。

Notice: Undefined index: idlights in C:\xampp\htdocs\lt4\checkbox\index.php on line 44

Warning: Invalid argument supplied for foreach() in C:\xampp\htdocs\lt4\checkbox\index.php on line 44

我如何验证此表，以便如果未选中任何内容，它只会显示类似“请选中复选框”或类似内容的内容？我试过了

if (empty($camid)

{

echo "<p style='color: red'>Please check a checkbox </p>";

}

但这没有用，这是我的代码，非常感谢对此的任何帮助

<?php

            include('conn.php');

                $query=mysqli_query($conn,"select * from `camera`");

                while($row=mysqli_fetch_array($query)){

                    ?>

                    <tr>

                        <td><input type="checkbox" value="<?php echo $row['camid']; ?>" name="camid[]"></td>

                        <td><?php echo $row['cameras']; ?></td>

                    </tr>

                    <?php

                }

            ?>

        </tbody>

    </table>

    <br>

    <input type="submit" name="submit" value="Submit">

    </form>

    </div>

    <div>

        <h2>You Booked:</h2>

        <?php

            if (isset($_POST['submit'])){

                foreach ($_POST['camid'] as $id):

                $sq=mysqli_query($conn,"select * from `camera` where camid='$id'");

                $srow=mysqli_fetch_array($sq);

                echo $srow['cameras']. "<br>";

                endforeach;

            }

        ?>

       ```

Answer 1

你使用任何框架吗？尝试在你的复选框中添加必需的<input&nbsp;type="checkbox"&nbsp;value="<?php&nbsp;echo&nbsp;$row['camid'];&nbsp;?>"&nbsp;name="camid[]"&nbsp;required>

Answer 2

只需使用如下所示的附加 if 语句。<?php&nbsp; &nbsp; &nbsp; &nbsp; if (isset($_POST['submit'])){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(isset($_POST['camid'])){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;foreach ($_POST['camid'] as $id):&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $sq=mysqli_query($conn,"select * from `camera` where camid='$id'");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; $srow=mysqli_fetch_array($sq);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; echo $srow['cameras']. "<br>";&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; endforeach;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; ?>