警告：mysqli::query()：无法在 C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php 第 43 行获取 mysqli 以下是我的连接......

警告：mysqli::query()：无法在 C:\Program Files (x86)\EasyPHP-DevServer-13.1VC9\data\localweb\my portable files\class_EventCalendar.php 第 43 行获取 mysqli

以下是我的连接文件：

<?php
if(!isset($_SESSION)) 
{ 
    session_start(); 
}  

// Create array to hold error messages (if any)
$ErrorMsgs = array();

// Create new mysql connection object
$DBConnect = @new mysqli("localhost","root@localhost", 
            NULL,"Ladle");

// Check to see if connection errno data member is not 0 (indicating an error)
if ($DBConnect->connect_errno) {

    // Add error to errors array
    $ErrorMsgs[]="The database server is not available.".
               " Connect Error is ".$DBConnect->connect_errno." ".
               $DBConnect->connect_error.".";
}
?>

这是我的课程：

 <?php 
    class EventCalendar {
        private $DBConnect = NULL;
        
        function __construct() {
            // Include the database connection data
            include("inc_LadleDB.php");
            $this->DBConnect = $DBConnect;  
        }
        
        function __destruct() {
            if (!$this->DBConnect->connect_error) {
                $this->DBConnect->close();
            }
        }
        
        function __wakeup() {
            // Include the database connection data
            include("inc_LadleDB.php");     
            $this->DBConnect = $DBConnect;
        }
        
        
        // Function to add events to Zodiac calendar
        public function addEvent($Date, $Title, $Description) {
            // Check to see if the required fields of Date and Title have been entered
            if ((!empty($Date)) && (!empty($Title))) {
                /* if all fields are complete then they are 
                   inserted into the Zodiac event_calendar table */
                $SQLString = "INSERT INTO tblSignUps".
                           " (EventDate, Title, Description) ".
                           " VALUES('$Date', '$Title', '".
                            $Description."')";
            
                // Store query results in a variable
                $QueryResult = $this->DBConnect->query($SQLString);

我不擅长使用 OOP PHP，我不确定为什么会出现此错误。我从其他地方提取了此代码，我唯一更改的是参数 @new mysqli 。有人能帮我了解出了什么问题吗？

在 PHP 8 上执行相同操作时，我发现类似的错误：

未捕获错误：mysqli 对象已关闭