我正在尝试用下拉列表创建一个古腾堡动态块。我已经完成了块的创建，并在前端使用选定的下拉值渲染块。

编辑帖子时，如何设置使用上一个值选择的下拉列表？

我尝试使用访问属性值props.attributes , 但是undefined

block.js

const { __ } = wp.i18n;
const { registerBlockType, RichText } = wp.blocks;

registerBlockType( \'gut/new-block\', {
    title: __( \'new-block - Test\' ),
    category: \'common\',
    attributes: {
        category_id: {
            type: \'number\'
        }
    },
    edit: function( props ) {
        const { attributes: { category_id }, setAttributes } = props;

        function setCategory( event ) {
            const selected = event.target.querySelector( \'option:checked\' );
            setAttributes( { category_id: selected.value } );
            event.preventDefault();
        }

        return (
            <div className={ props.className }>                            
                <select value={ category_id } onChange={ setCategory }>
                    <option value="120">Animals</option>
                    <option value="350">Architecture</option>
                    <option value="700">Nature</option>
                    <option value="800">People</option>
                    <option value="432">Tech</option>
                </select>                
            </div>
        );
    },
    save ( props ) {
        return null
    },
});

PHP

function gut_my_new_block() {
    wp_register_script(
        \'gut-my-new-block\',
        plugins_url( \'new-block/dist/blocks.build.js\', __FILE__ ),
        array( \'wp-blocks\', \'wp-element\' )
    );

    register_block_type( \'gut/new-block\', array(
        \'render_callback\' => \'gut_render_block_my_newblock\',
        \'editor_script\' => \'gut-my-new-block\',
    ) );
}

add_action( \'init\', \'gut_my_new_block\' );

function gut_render_block_my_newblock($params) {  
    return \'<h3>selected category \'.$params[\'category_id\'].\'</h3>\';
}