<?php
global $post;
foreach ($event_photos_obj as $post) :
...
...
// set up product in order to use native wordpress api
setup_postdata($post);
/* Include the single view for the product (photo). */
include .....
endforeach;
wp_reset_postdata();?>
my mistake my code is that setup_postdata with $product instead of $post as the tutorial said : https://codex.wordpress.org/Function_Reference/setup_postdata
This is one way, the second way uses WP_Query http://codex.wordpress.org/Class_Reference/WP_Query
but in my case I don’t need because I have already the object from the WP E-Commenrce with his functions and everything.