这是代码。您可以根据需要更改$post\\u type和$custom\\u字段。

function extend_admin_search( $query ) {

    // Extend search for document post type
    $post_type = \'document\';
    // Custom fields to search for
    $custom_fields = array(
        "_file_name",
    );

    if( ! is_admin() )
        return;

    if ( $query->query[\'post_type\'] != $post_type )
        return;

    $search_term = $query->query_vars[\'s\'];

    // Set to empty, otherwise it won\'t find anything
    $query->query_vars[\'s\'] = \'\';

    if ( $search_term != \'\' ) {
        $meta_query = array( \'relation\' => \'OR\' );

        foreach( $custom_fields as $custom_field ) {
            array_push( $meta_query, array(
                \'key\' => $custom_field,
                \'value\' => $search_term,
                \'compare\' => \'LIKE\'
            ));
        }

        $query->set( \'meta_query\', $meta_query );
    };
}

add_action( \'pre_get_posts\', \'extend_admin_search\' );