By pulling multiple taxonomies lists into the sidebar you can easily create simple filtering, without the need for a form or modifying the results query. Example:
<div class="sidebar">
<h4 >Resources by category</h4>
<ul>
<?php wp_list_categories( array(
'orderby' => 'name',
'hierarchical' => true,
'style' => 'list',
'hide_empty' => 0,
'show_count' => 0,
'title_li' => ''
) ); ?>
</ul>
</div>Note: This route only allows you to filter by one criteria/category each time.
To add custom taxonomies you can use get_categories to create a comma separated list:
<h4>Tagged by file type</h4>
<p>
<?php
$args = array(
'orderby' => 'name',
'hierarchical' => true,
'taxonomy' => 'types-category',
'title_li' => __( 'Categories' ),
'separator' => '',
'echo' => 0,
'style' => '',
'hide_empty' => 1,
);
get_categories($args);
$categories = get_categories( $args );
$items = array();
foreach($categories as $category) {
$items[] = sprintf( '<a href="%1$s">%2$s</a>',
esc_url( get_category_link( $category->term_id ) ),
esc_html( $category->name )
);
}
echo implode(", ", $items);
?>
</p>
<h4>Tagged by style</h4>
<p>
<?php
$args = array(
'orderby' => 'name',
'hierarchical' => true,
'taxonomy' => 'styles-category',
'title_li' => __( 'Categories' ),
'separator' => '',
'echo' => 0,
'style' => '',
'hide_empty' => 1,
);
get_categories($args);
$categories = get_categories( $args );
$items = array();
foreach($categories as $category) {
$items[] = sprintf( '<a href="%1$s">%2$s</a>',
esc_url( get_category_link( $category->term_id ) ),
esc_html( $category->name )
);
}
echo implode(", ", $items);
?>
</p>
<h4>Tagged by person</h4>
<p>
<?php
$args = array(
'orderby' => 'name',
'hierarchical' => true,
'taxonomy' => 'people-category',
'title_li' => __( 'Categories' ),
'separator' => '',
'echo' => 0,
'style' => '',
'hide_empty' => 1,
);
get_categories($args);
$categories = get_categories( $args );
$items = array();
foreach($categories as $category) {
$items[] = sprintf( '<a href="%1$s">%2$s</a>',
esc_url( get_category_link( $category->term_id ) ),
esc_html( $category->name )
);
}
echo implode(", ", $items);
?>
</p>All results are shown using the archive.php page but you can use category.php, tag.php, author.php or taxonomy-XXX.php pages to create different results pages if you wish.