after setup_postdata, the_content() only displays text before the read more tag

Question

I'm building a traveling-page and i need to add the description of a train or a ship into the description of a trip. My code looks like this:

<?php if (!empty(rwmb_meta("train_ship"))) { ?>
   <div class="maxtext_detail">
      <?php $get_train = get_post( get_post_meta( $post->ID, "train_ship", true) );
      setup_postdata( $get_train ); ?>
      <h3><?php the_title(); ?></h3>
      <p><?php the_content(); ?><a href="#" data-toggle="modal" data-target="#myModal">Read More</a></p>
   </div>

   <!-- Modal -->
   <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel">
     <div class="modal-dialog" role="document">
        <div class="modal-content">
           <div class="modal-header">
              <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
              <h4 class="modal-title" id="myModalLabel"><?php the_title(); ?></h4>
           </div>
         <div class="modal-body">
       <?php the_content(); ?>
     </div>
   </div>
 </div>

This is inside the Loop of a single.php. My problem is that the content only displays the text before the "read more" tag that I added to the post of the train. This is actually what i want to do with the first the_content, but the second should display the full content. Does anyone know why only the parts before the read more are displayed?

Thanks for your help

Answer 1

Check out the examples on the setup_postdata Codex page. You must pass a reference to the global $post, it won't work with any other variable.

global $post;            // make sure we're working with the global.
$post = $get_train;      // or assign get_post result directly to $post.
setup_postdata( $post ); // this must be the global $post.