如果您不介意强制下载所有PDF附件，那么您可以使用以下内容：

<?php
if (have_posts()) : while (have_posts()) : the_post();

    $pdf_title = $post->post_title;
    $uploads_dir = wp_upload_dir();
    $attachment_src = get_post_meta( $post->ID, \'_wp_attached_file\', true );
    $pdf_src = path_join( $uploads_dir[\'basedir\'], $attachment_src );
    header("Pragma: public"); // required
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: private",false); // required for certain browsers 
    header("Content-Type: application/pdf");
    header("Content-Disposition: attachment; filename=\\"".$pdf_title."\\";" );
    header("Content-Transfer-Encoding: binary");
    header("Content-Length: ".filesize($pdf_src));
    ob_clean();
    flush();
    readfile($pdf_src);

endwhile; endif;
?>

将上述代码放入名为pdf的文件中。当前主题文件夹中的php。而不是直接链接到pdf(http://example.com/wp-content/uploads/2011/01/Guide-to-Owning-a-Listed-Building.pdf)，链接到附件URL：(http://example.com/help-and-advice/attachment/guide-to-owning-a-listed-building/)

按照上面的操作，您可以编辑代码来执行其他奇特的操作，例如跟踪下载，并添加某种级别的身份验证，同时保护PDF的实际位置。