php 发送带pdf附件的email 出现的是一长串字符串 请教怎么解决

php 发送带pdf附件的email 出现的是一长串字符串 请问如何解决
RT，发出的email附件不是一个pdf档，而变成了一长串字符串，

我的发送email的代码如下：

function mail($mailto, $userid, $data){
    global $dsql,$cfg_adminemail,$cfg_webname,$cfg_basehost,$cfg_memberurl;
    $mailtitle = $cfg_webname.":通知";
$file=fopen("D:/xampp/htdocs/pdftemp/dsfasdf.pdf","r"); 
$fileName=$data['oid'].'.pdf';
$mimeType ="application/pdf"; 
$boundary = "nextpart_".uniqid("");  //分隔符1
$boundary2 = "nextpart2_".uniqid(""); //分隔符2

        //email头
$headers = "From: ".$cfg_adminemail."\r\nReply-To: $cfg_adminemail";
$headers .= "Content-type: multipart/mixed; boundary=\"$boundary1\"\r\n";

        //读取文件
        $read = fread($file, filesize("D:/xampp/htdocs/pdftemp/dsfasdf.pdf")); 
//我们用base64方法把它编码 
$read = base64_encode($read); 
//把这个长字符串切成由每行76个字符组成的小块 
$read = chunk_split($read);

        //以下是mailbody正文 
$mailbody = "--$boundary1----$boundary2 
Content-type: text/plain;charset=iso-8859-1;
Content-transfer-encoding: 8bit";
    $mailbody .= '致： '.$userid.',



This is mailbody--$boundary2--';
        
        //以下是附件部分
$mailbody .="--$boundary1 
Content-type: text/html; name=$fileName 
Content-disposition: inline; filename=$fileName 
Content-transfer-encoding: 8bit
$read 
--$boundary1--";


    $status = smail($mailto,$mailtitle,$mailbody,$headers);
    setMail($mailto, $mailtitle, $mailbody, $headers, $status);
    return $status;
}

<br />
// attachment<br />
$body .= "--".$separator.$eol;<br />
$body .= "Content-Type: application/octet-stream; name=\"".$filename."\"".$eol; <br />
$body .= "Content-Transfer-Encoding: base64".$eol;<br />
$body .= "Content-Disposition: attachment".$eol.$eol;<br />
$body .= $attachment.$eol;<br />
$body .= "--".$separator."--";

$email = new PHPMailer();<br />
$email->From      = 'you@example.com';<br />
$email->FromName  = 'Your Name';<br />
$email->Subject   = 'Message Subject';<br />
$email->Body      = $bodytext;<br />
$email->AddAddress( 'destinationaddress@example.com' );<br />
<br />
$file_to_attach = 'PATH_OF_YOUR_FILE_HERE';<br />
<br />
$email->AddAttachment( $file_to_attach , 'NameOfFile.pdf' );<br />
<br />
return $email->Send();