wp_dropdown_categories() 默认情况下，将按id列出。它利用get_terms() 如果您希望过滤$output 超出参数允许的范围。（我在下面添加了来源）。

它具有以下参数：

显示用于显示所有类别的“show\\u option\\u all”（字符串）文本<要显示的“show\\u option\\u none”（字符串）文本，用于不显示类别

\'option\\u none\\u value\'（字符串）在未选择类别时使用的值

\'orderby\' （字符串）Which column to use for ordering categories. See get_terms() for a list of accepted values. Default \'id\' (term_id).“显示计数”（bool | int）是否包括post计数。接受0、1或其布尔等价项。默认值0

\'hide\\u empty\'（bool | int）是否隐藏没有任何帖子的类别。接受0、1或其布尔等价项。默认值1

\'child\\u of\'（int）要检索的子项的项ID。请参阅get\\u terms（）。默认值0

\'exclude\'（数组|字符串）数组或要排除的术语ID的逗号/空格分隔字符串。如果$include非空，则忽略$exclude。默认空数组

“echo”（bool | int）是回显还是返回生成的标记。接受0、1或其布尔等价项。默认值1“层次”（bool | int）是否遍历分类层次。接受0、1或其布尔等价项。默认值0

选择元素的“tab\\u index”（int）选项卡索引。默认值0（无tabindex）

\'id\' （字符串）的值\'id\' attribute of the select element. 默认值为$name

\'class\' （字符串）的值\'class\' attribute of the select element. 默认“postform”

\'hide\\u if\\u empty\'（bool）True，如果找不到类别，则跳过生成标记。默认为false（即使找不到类别，也创建select元素）

\'required\'（bool）元素是否应该具有HTML5的“required”属性。默认值为false

<人力资源>

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,
    );

    $defaults[\'selected\'] = ( is_category() ) ? get_query_var( \'cat\' ) : 0;

    // Back compat.
    if ( isset( $args[\'type\'] ) && \'link\' == $args[\'type\'] ) {
        _deprecated_argument( __FUNCTION__, \'3.0.0\',
            /* translators: 1: "type => link", 2: "taxonomy => link_category" */
            sprintf( __( \'%1$s is deprecated. Use %2$s instead.\' ),
                \'<code>type => link</code>\',
                \'<code>taxonomy => link_category</code>\'
            )
        );
        $args[\'taxonomy\'] = \'link_category\';
    }

    $r = wp_parse_args( $args, $defaults );
    $option_none_value = $r[\'option_none_value\'];

    if ( ! isset( $r[\'pad_counts\'] ) && $r[\'show_count\'] && $r[\'hierarchical\'] ) {
        $r[\'pad_counts\'] = true;
    }

    $tab_index = $r[\'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 = $r;
    unset( $get_terms_args[\'name\'] );
    $categories = get_terms( $r[\'taxonomy\'], $get_terms_args );

    $name = esc_attr( $r[\'name\'] );
    $class = esc_attr( $r[\'class\'] );
    $id = $r[\'id\'] ? esc_attr( $r[\'id\'] ) : $name;
    $required = $r[\'required\'] ? \'required\' : \'\';

    if ( ! $r[\'hide_if_empty\'] || ! empty( $categories ) ) {
        $output = "<select $required name=\'$name\' id=\'$id\' class=\'$class\' $tab_index_attribute>\\n";
    } else {
        $output = \'\';
    }
    if ( empty( $categories ) && ! $r[\'hide_if_empty\'] && ! empty( $r[\'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 Taxonomy element to list.
         */
        $show_option_none = apply_filters( \'list_cats\', $r[\'show_option_none\'] );
        $output .= "\\t<option value=\'" . esc_attr( $option_none_value ) . "\' selected=\'selected\'>$show_option_none</option>\\n";
    }

    if ( ! empty( $categories ) ) {

        if ( $r[\'show_option_all\'] ) {

            /** This filter is documented in wp-includes/category-template.php */
            $show_option_all = apply_filters( \'list_cats\', $r[\'show_option_all\'] );
            $selected = ( \'0\' === strval($r[\'selected\']) ) ? " selected=\'selected\'" : \'\';
            $output .= "\\t<option value=\'0\'$selected>$show_option_all</option>\\n";
        }

        if ( $r[\'show_option_none\'] ) {

            /** This filter is documented in wp-includes/category-template.php */
            $show_option_none = apply_filters( \'list_cats\', $r[\'show_option_none\'] );
            $selected = selected( $option_none_value, $r[\'selected\'], false );
            $output .= "\\t<option value=\'" . esc_attr( $option_none_value ) . "\'$selected>$show_option_none</option>\\n";
        }

        if ( $r[\'hierarchical\'] ) {
            $depth = $r[\'depth\'];  // Walk the full depth.
        } else {
            $depth = -1; // Flat.
        }
        $output .= walk_category_dropdown_tree( $categories, $depth, $r );
    }

    if ( ! $r[\'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  $r      Arguments used to build the drop-down.
     */
    $output = apply_filters( \'wp_dropdown_cats\', $output, $r );

    if ( $r[\'echo\'] ) {
        echo $output;
    }
    return $output;
}