Displays or retrieves the HTML dropdown list of categories.
Description
The ‘hierarchical’ argument, which is disabled by default, will override the depth argument, unless it is true. When the argument is false, it will display all of the categories. When it is enabled it will use the value in the ‘depth’ argument.
Parameters
$argsarray|stringoptional- Array or string of arguments to generate a categories drop-down element. See WP_Term_Query::__construct() for information on additional accepted arguments.
show_option_allstringText to display for showing all categories.show_option_nonestringText to display for showing no categories.option_none_valuestringValue to use when no category is selected.orderbystringWhich column to use for ordering categories. See get_terms() for a list of accepted values. Default'id'(term_id).pad_countsboolSee get_terms() for an argument description. Default false.show_countbool|intWhether to include post counts. Accepts 0, 1, or their bool equivalents.
Default 0.echobool|intWhether to echo or return the generated markup. Accepts 0, 1, or their bool equivalents. Default 1.hierarchicalbool|intWhether to traverse the taxonomy hierarchy. Accepts 0, 1, or their bool equivalents. Default 0.depthintMaximum depth. Default 0.tab_indexintTab index for the select element. Default 0 (no tabindex).namestringValue for the'name'attribute of the select element. Default'cat'.idstringValue for the'id'attribute of the select element. Defaults to the value of$name.classstringValue for the'class'attribute of the select element. Default'postform'.selectedint|stringValue of the option that should be selected. Default 0.value_fieldstringTerm field that should be used to populate the'value'attribute of the option elements. Accepts any valid term field:'term_id','name','slug','term_group','term_taxonomy_id','taxonomy','description','parent','count'. Default'term_id'.taxonomystring|arrayName of the taxonomy or taxonomies to retrieve. Default'category'.hide_if_emptyboolTrue to skip generating markup if no categories are found.
Default false (create select element even if no categories are found).requiredboolWhether the<select>element should have the HTML5'required'attribute.
Default false.walkerWalkerWalker object to use to build the output. Default empty which results in a Walker_CategoryDropdown instance being used.aria_describedbystringThe'id'of an element that contains descriptive text for the select.
More Arguments from get_terms( … $args )
Array or string of arguments. See WP_Term_Query::__construct() for information on accepted arguments.Default:
''
Source
function wp_dropdown_categories( $args = '' ) {
$defaults = array(
'show_option_all' => '',
'show_option_none' => '',
'orderby' => 'id',
'order' => 'ASC',
'show_count' => 0,
'hide_empty' => 1,
'child_of' => 0,
'exclude' => '',
'echo' => 1,
'selected' => 0,
'hierarchical' => 0,
'name' => 'cat',
'id' => '',
'class' => 'postform',
'depth' => 0,
'tab_index' => 0,
'taxonomy' => 'category',
'hide_if_empty' => false,
'option_none_value' => -1,
'value_field' => 'term_id',
'required' => false,
'aria_describedby' => '',
);
$defaults['selected'] = ( is_category() ) ? get_query_var( 'cat' ) : 0;
// Back compat.
if ( isset( $args['type'] ) && 'link' === $args['type'] ) {
_deprecated_argument(
__FUNCTION__,
'3.0.0',
sprintf(
/* translators: 1: "type => link", 2: "taxonomy => link_category" */
__( '%1$s is deprecated. Use %2$s instead.' ),
'<code>type => link</code>',
'<code>taxonomy => link_category</code>'
)
);
$args['taxonomy'] = 'link_category';
}
// Parse incoming $args into an array and merge it with $defaults.
$parsed_args = wp_parse_args( $args, $defaults );
$option_none_value = $parsed_args['option_none_value'];
if ( ! isset( $parsed_args['pad_counts'] ) && $parsed_args['show_count'] && $parsed_args['hierarchical'] ) {
$parsed_args['pad_counts'] = true;
}
$tab_index = $parsed_args['tab_index'];
$tab_index_attribute = '';
if ( (int) $tab_index > 0 ) {
$tab_index_attribute = " tabindex=\"$tab_index\"";
}
// Avoid clashes with the 'name' param of get_terms().
$get_terms_args = $parsed_args;
unset( $get_terms_args['name'] );
$categories = get_terms( $get_terms_args );
$name = esc_attr( $parsed_args['name'] );
$class = esc_attr( $parsed_args['class'] );
$id = $parsed_args['id'] ? esc_attr( $parsed_args['id'] ) : $name;
$required = $parsed_args['required'] ? 'required' : '';
$aria_describedby_attribute = $parsed_args['aria_describedby'] ? ' aria-describedby="' . esc_attr( $parsed_args['aria_describedby'] ) . '"' : '';
if ( ! $parsed_args['hide_if_empty'] || ! empty( $categories ) ) {
$output = "<select $required name='$name' id='$id' class='$class'$tab_index_attribute$aria_describedby_attribute>\n";
} else {
$output = '';
}
if ( empty( $categories ) && ! $parsed_args['hide_if_empty'] && ! empty( $parsed_args['show_option_none'] ) ) {
/**
* Filters a taxonomy drop-down display element.
*
* A variety of taxonomy drop-down display elements can be modified
* just prior to display via this filter. Filterable arguments include
* 'show_option_none', 'show_option_all', and various forms of the
* term name.
*
* @since 1.2.0
*
* @see wp_dropdown_categories()
*
* @param string $element Category name.
* @param WP_Term|null $category The category object, or null if there's no corresponding category.
*/
$show_option_none = apply_filters( 'list_cats', $parsed_args['show_option_none'], null );
$output .= "\t<option value='" . esc_attr( $option_none_value ) . "' selected='selected'>$show_option_none</option>\n";
}
if ( ! empty( $categories ) ) {
if ( $parsed_args['show_option_all'] ) {
/** This filter is documented in wp-includes/category-template.php */
$show_option_all = apply_filters( 'list_cats', $parsed_args['show_option_all'], null );
$selected = ( '0' === (string) $parsed_args['selected'] ) ? " selected='selected'" : '';
$output .= "\t<option value='0'$selected>$show_option_all</option>\n";
}
if ( $parsed_args['show_option_none'] ) {
/** This filter is documented in wp-includes/category-template.php */
$show_option_none = apply_filters( 'list_cats', $parsed_args['show_option_none'], null );
$selected = selected( $option_none_value, $parsed_args['selected'], false );
$output .= "\t<option value='" . esc_attr( $option_none_value ) . "'$selected>$show_option_none</option>\n";
}
if ( $parsed_args['hierarchical'] ) {
$depth = $parsed_args['depth']; // Walk the full depth.
} else {
$depth = -1; // Flat.
}
$output .= walk_category_dropdown_tree( $categories, $depth, $parsed_args );
}
if ( ! $parsed_args['hide_if_empty'] || ! empty( $categories ) ) {
$output .= "</select>\n";
}
/**
* Filters the taxonomy drop-down output.
*
* @since 2.1.0
*
* @param string $output HTML output.
* @param array $parsed_args Arguments used to build the drop-down.
*/
$output = apply_filters( 'wp_dropdown_cats', $output, $parsed_args );
if ( $parsed_args['echo'] ) {
echo $output;
}
return $output;
}
Hooks
- apply_filters( ‘list_cats’,
string $element ,WP_Term|null $category ) Filters a taxonomy drop-down display element.
- apply_filters( ‘wp_dropdown_cats’,
string $output ,array $parsed_args ) Filters the taxonomy drop-down output.
This example displays a category dropdown list using JavaScript instead of a submit button, with a no-selection option (labeled: “Select category”):
By default,
wp_dropdown_categoriesonly returns categories that have been assigned to at least one post. To override this set thehide_emptyparameter to false ("0").In this example the echo parameter (
echo=0) is used. A simplepreg_replaceinserts the JavaScript code. It even works without JavaScript (submit button is wrapped bynoscripttags).You can use Walker with this wp_dropdown_categories function.
Example –
With the following example you add a selected to the current tag archive page.
With the following example, when category is selected, you can automatically redirect to the category detail page.
For anyone looking for the description for the
pad_countsarg, it is found on the Constructor of WP_Term_Query.Displays a hierarchical category dropdown list in an HTML select form with a submit button, with a count of posts in each category.
It’s
hide_emptyNOThide_if_empty!In the args’ Parameters list.