WooCommerce。 如何使用（do_shortcode）在单个产品页面中打开产品页面？

I have a product page from WooCommerce plugin and when I try to add this product page to my theme's single page it doesn't appear.

I'm using this code:

<?php echo do_shortcode( '[product_page id="2279"]' );?>

If I add this code to single-game.php it works:

<div id="primary" class="content-area">
                    <div class="inner">
                        <?php $posts = tfuse_get_game_news($post->ID);?>
                        <?php echo do_shortcode( '[product_page id="2279"]' );?>


                        <?php if(get_option('posts_per_page') < count($posts)):?>
                            <div class="load_button">
                                <button type="submit" class="btn btn-main" id="load_game_posts" data-post-id="<?php echo $post->ID;?>" data-from="game_buyy" value=""><?php _e('Load More', 'tfuse'); ?></button>
                                <button type="submit" class="btn btn-main" id="loading_game_posts"><?php _e('Loading...', 'tfuse'); ?></button>
                            </div>
                        <?php endif;?>
                    </div>
                </div>

But, when I try to add same code to AJAX_CALLBACKS.php file:

elseif($tax == 'game_buy')
    {
        $posts = tfuse_get_game_posts($post_id,'Buy Now');

        echo do_shortcode( '[product_page id="2279"]' );

    }

I get a blank screen without anything.

I have tried this code:

echo do_shortcode( '[product_page id="2279"]' );

<?php echo do_shortcode( '[product_page id="2279"]' );?>

I expect when I click on the "buy now" button that it would show my product.