Php Wordpress主题函数在调用时不工作

我有一个wordpress站点，我想在我的functions.php中保存并进行数据库连接

<?php 

   function dbconnd() {

   $server = "localhost";
   $duser = "wpuser";
   $dpass = "wppass";
   $dbname = "wpdb";

   $conn = new mysqli($server, $duser,$dpass, $dbname);
   // Check connection
   if ($conn->connect_error) {
       die("Connection failed: " . $conn->connect_error);
   }

   }

?>

所以我可以在我的模板中调用它。 以下是functions.php中的函数代码

<?php 

   function dbconnd() {

   $server = "localhost";
   $duser = "wpuser";
   $dpass = "wppass";
   $dbname = "wpdb";

   $conn = new mysqli($server, $duser,$dpass, $dbname);
   // Check connection
   if ($conn->connect_error) {
       die("Connection failed: " . $conn->connect_error);
   }

   }

?>

但在下面的情况下，当我不调用该函数时，它可以完美地工作

 <?php
   $server = "localhost";
   $duser = "wpuser";
   $dpass = "wppass";
   $dbname = "wpdb";
   $conn = new mysqli($server, $duser,$dpass, $dbname);
   // Check connection
   if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
   }
   $sql = "SELECT * FROM orderform WHERE status='last';";
   $result = $conn->query($sql); 
 ?>

---

按照您现在的操作方式，
$conn
只是函数内部的局部变量。因此，您无法通过这种方式获得函数外部的值

最好的解决办法是：

   function dbconnd() {

   $server = "localhost";
   $duser = "wpuser";
   $dpass = "wppass";
   $dbname = "wpdb";

   $conn = new mysqli($server, $duser,$dpass, $dbname);
   // Check connection
   if ($conn->connect_error) {
       die("Connection failed: " . $conn->connect_error);
   }
   else
   return $conn;

   }

然后在调用函数时，运行以下命令：

$conn = dbconnd();

另外，不要忘记在调用它的php文件中包含或要求functions.php文件。
您可以使用class运行raw
SQL
。（
）它现在工作得很好，我没有包括require functions.php，只有$conn=dbconnd（）；包括康恩的回报，谢谢