當我過去使用簡單文本正文發(fā)送不帶附件的電子郵件時，出現(xiàn)消息無法發(fā)送的錯誤。郵件程序錯誤：無法訪問文件：./attachment/如果我評論我的附件功能，我的代碼工作正常。$mail->send 函數(shù)每次都會嘗試搜索附件文件夾。即使文件不存在于電子郵件中，即文件僅包含文本。<?php    include('db.php');use PHPMailer\PHPMailer\PHPMailer;use PHPMailer\PHPMailer\Exception;require_once "vendor/autoload.php";    $id = $_GET['id'];    $query = "select * from access where uid='$id'";$result = mysqli_query($conn,$query);$row = mysqli_fetch_assoc($result);    $mail = new PHPMailer(true);    try {        $mail->setFrom('sender@gmail.com');  $mail->addAddress('receiver@gmail.com');      $array = explode(", ",$row['attachments']);  $count = count($array);  if($count > 0 && $row['attachments'] != 'null'){    for ($i=0; $i < $count ; $i++) {      $file_to_attach = './attachment/' . $array[$i];      $mail->addAttachment($file_to_attach, $array[$i]);     }  }      $mail->isHTML(true);                                    $mail->Subject = $row['subject'];  $mail->Body    = $row['body'];      $mail->send();  echo 'Message has been sent';} catch (Exception $e) {  echo "Message could not be sent. Mailer Error: {$mail->ErrorInfo}";}