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_all string
  Text to display for showing all categories.
• show_option_none string
  Text to display for showing no categories.
• option_none_value string
  Value to use when no category is selected.
• orderby string
  Which column to use for ordering categories. See get_terms() for a list of accepted values. Default 'id' (term_id).
• pad_counts bool
  See get_terms() for an argument description. Default false.
• show_count bool|int
  Whether to include post counts. Accepts 0, 1, or their bool equivalents.
  Default 0.
• echo bool|int
  Whether to echo or return the generated markup. Accepts 0, 1, or their bool equivalents. Default 1.
• hierarchical bool|int
  Whether to traverse the taxonomy hierarchy. Accepts 0, 1, or their bool equivalents. Default 0.
• depth int
  Maximum depth. Default 0.
• tab_index int
  Tab index for the select element. Default 0 (no tabindex).
• name string
  Value for the 'name' attribute of the select element. Default 'cat'.
• id string
  Value for the 'id' attribute of the select element. Defaults to the value of $name.
• class string
  Value for the 'class' attribute of the select element. Default 'postform'.
• selected int|string
  Value of the option that should be selected. Default 0.
• value_field string
  Term 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'.
• taxonomy string|array
  Name of the taxonomy or taxonomies to retrieve. Default 'category'.
• hide_if_empty bool
  True to skip generating markup if no categories are found.
  Default false (create select element even if no categories are found).
• required bool
  Whether the <select> element should have the HTML5 'required' attribute.
  Default false.
• walker Walker
  Walker object to use to build the output. Default empty which results in a Walker_CategoryDropdown instance being used.
• aria_describedby string
  The '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:''

Return

More Information

If you want to allow users to select multiple values, use wp_category_checklist().

The wp_dropdown_cats filter is applied to the output string before it is echoed/returned.

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;
}

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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.

Changelog