Limit Category/Tag Dropdown To blog_id in Multisite Install With Global Categories/Tags

Question

I am using this function to make categories and tags global on my multisite installation.

An unfortunate side effect of global categories/tags is that it displays categories for posts across all sites. This creates two undesirable problems:

1. It shows categories/tags that the current blog has no posts for, linking to an archive with a 'not found' message.
2. For count, WordPress looks at all of the blogs in the network, finds the highest total for each category/tag from all blogs within the network and displays that number.

When I display categories or tags in a dropdown on an individual site, I only want categories from the current blog_id to show in the list with the count from the number of corresponding posts in the current blog.

I have tried to limit the posts in a category dropdown with meta_query, but it's not working for me:

<form id="category-select" class="category-select" action="<?php echo esc_url( home_url( '/' ) ); ?>" method="get">
    $blog_id = get_current_blog_id();
    $args = array(
        'show_option_none' => __( 'Select Category' ),
        'show_count'       => 1,
        'orderby'          => 'name',
        'echo'             => 0,
        'meta_query'       => array(
            'key'     => 'blog_id',
            'value'   => $blog_id,
            'compare' => '=')
    );
    $select  = wp_dropdown_categories( $args );
    $replace = "<select$1 onchange='return this.form.submit()'>";
    $select  = preg_replace( '#<select([^>]*)>#', $replace, $select );

    <noscript>
        <input type="submit" value="View" />
    </noscript>
</form>

Any way to modify this meta_query parameter or tackle this from another angle?

Answer 1

The wp_dropdown_category seems to not accept the mera_query parameter codex Maybe you must perform à special query , note that the meta_query must be an array of array.

 'meta_query'=> array(
       array(
         'key'     => 'blog_id',
        'value'   => $blog_id,
        'compare' => '='
       )
 ),

With the new query you'll be able to compose your dropdown by looping through result.

WP_Query custom field parameter

Hope it works with this ?

Answer 2

I know there has to be a better way, but this is what I could come up with. I'm not referencing blog_id at all, but I have to loop through all the posts on the current blog, category by category:

<form id="category-select" class="category-select" action="<?php echo esc_url( home_url( '/' ) ); ?>" method="get">
    <select class="postform" name="categories-dropdown" onChange='document.location.href=this.options[this.selectedIndex].value;'>
        <option value=""><?php echo attribute_escape(__('Select Category')); ?></option>
            <?php
            $categories = get_categories( array(
                'orderby' => 'name',
                'order'   => 'ASC'
            ) );
            foreach( $categories as $category ) {
                $args = array(
                    'posts_per_page' => -1,
                    'category' => $category->term_id);
                $posts = get_posts($args);
                $ct = 0;
                foreach ($posts as $post) {
                    $ct++;
                }
                $c_list = '<option value="'.get_category_link($category->term_id).'">';
                $c_list .= $category->name.' ('.$ct.')';
                $c_list .= '</option>';

                if($ct > 0) { echo $c_list; }
          } 
          ?>
    </select>
</form>