相关疑难解决方法(0)

我基本上编码了一个代码,该代码填充了我的数据库中的类别列表,然后您就可以选择要删除的类别.

我有删除代码的问题,由于错误似乎无法正常工作:

Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in F:\xamppnew\htdocs\650032\admin\delete.php on line 6

造成这种情况的一行是:

if(isset($_POST['delete_id'] && !empty($_POST['delete_id']))) {

deletecategory.php

    <h3>
     Delete Category
    </h3>

    <?php $result = mysql_query("SELECT * FROM category"); ?>

<table>
  <?php while($row = mysql_fetch_array($result)) : ?>
  <tr id="<?php echo $row['category_id']; ?>">
    <td><?php echo $row['category_Name']; ?></td>
    <td>
      <button class="del_btn" rel="<?php echo $row['id']; ?>">Delete</button>
    </td>
  </tr>
  <?php endwhile; ?>
</table>

<script>
  $(document).ready(function(){
    $('.del_btn').click(function(){
       var del_id = $(this).attr('rel');
       $.post('delete.php', …

我在从SF2.0.x迁移到SF2.7的应用程序中收到此错误:

[1] Symfony\Component\Debug\Exception\FatalErrorException: Compile Error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead)
    at n/a
        in /var/www/html/reptooln_admin/app/cache/dev/twig/68/7f/63589dd3687cb849dd68e6b6c10aa99eda1d82f95a5f3ac52a864d200499.php line 39

我不知道什么是失败或如何解决这个问题所以我需要一些建议.这是报告Stacktrace的缓存文件中的行:

    if ((((empty((isset($context["form_action"]) ? $context["form_action"] : $this->getContext($context, "form_action"))) == true) || (isnull((isset($context["form_action"]) ? $context["form_action"] : $this->getContext($context, "form_action"))) == true)) || (isset((isset($context["form_action"]) ? $context["form_action"] : $this->getContext($context, "form_action"))) == false))) {
                echo " ";
                $context["form_action"] = "";
                echo " ";

我有这个TwigExtension:

class PDOneTwigExtension extends \Twig_Extension
{
    public function getFilters()
    {
        return array(
            'var_dump'   => new …