php Isset 表达式错误
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Isset expression error
提问by user3411002
I have basically coded a code which populates a list of categories from my database then you are able to select which to delete.
我基本上编写了一个代码，该代码从我的数据库中填充类别列表，然后您就可以选择要删除的类别。
I have the issue with the delete code which does not seem to work due to the error:
我有删除代码的问题，由于错误，它似乎不起作用：
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in F:\xamppnew\htdocs0032\admin\delete.php on line 6
The line causing this is:
导致这种情况的行是：
if(isset($_POST['delete_id'] && !empty($_POST['delete_id']))) {
deletecategory.php
删除类别.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', {delete_id:del_id}, function(data) {
if(data == 'true') {
$('#'+del_id).remove();
} else {
alert('Could not delete!');
}
});
});
});
</script>
delete.php
删除.php
<?php
if(isset($_POST['delete_id'] && !empty($_POST['delete_id']))) {
$delete_id = mysql_real_escape_string($_POST['delete_id']);
$result = mysql_query("DELETE FROM category WHERE `id`=".$delete_id);
if($result !== false) {
echo 'true';
}
}
?>
回答by Jason OOO
You missed this ):
你错过了这个)：
if(isset($_POST['delete_id']) && !empty($_POST['delete_id']))
^---
回答by AbraCadaver
Others have shown the issue of the missing )in the expression, but empty()will check isset()so that is redundant. Just check empty():
其他人已经显示了)表达式中缺少的问题，但empty()会检查isset()它是多余的。只需检查empty()：
if(!empty($_POST['delete_id'])) {
回答by dave
The issue is that this
问题是这
if(isset($_POST['delete_id'] && !empty($_POST['delete_id'])))
should be
应该
if(isset($_POST['delete_id']) && !empty($_POST['delete_id']))
