Question

因此，我试图在PHP中为一个网站构建一个动态下拉列表，它来自我的数据库中的一个类别数组，并且它正在工作，并且我得到了7个确切类型（7是我拥有的类别数量）。下面是代码：

<?php 
$categories = getCategories(); 

$catList = '<select name="categoryId" id="categoryId">'; 
$catList .= '<option>Choose a Category</option>'; 

    foreach ($categories as $category){ 
    $catList .= "<option value='$category[categoryId]'"; 
     if(isset($categoryId)){ 
     if(category['categoryId'] === "$categoryId"){ 
      $catList .= ' selected '; 
     } 
     } 
    $catList .= ">$category[categoryName]</option>"; 
    } 
$catList .= "</select>"; 
?> 

，这里是错误消息：

Notice: Use of undefined constant category - assumed 'category' in 
C:\my\path\to\the\addproduct.php on line 8 

Warning: Illegal string offset 'categoryId' in 
C:\my\path\to\the\addproduct.php on line 8 

作为参考，8号线是if(category['categoryId'] === $categoryId){

Answer 1

你有8行错字你忘记在类别前添加$。记住它是一个PHP变量。将其更改为以下

if($category['categoryId'] === "$categoryId"){ 

Answer 2

变化

if(category['categoryId'] === "$categoryId"){ 

到

if($category['categoryId'] === "$categoryId"){