I think you are executing reset_postdata()
too early, using the global $post
object incorrectly inside the secondary loop and passing wrong argumentes to the secondary loop. Try this.
Put the function to get the latest author posts in the functions.php file:
function the_latest_author_posts($post) {
//some content goes here regarding the post itself!!!
$relatedargs = array(
'author' => $post->post_author,
'post__not_in' => array( $post->ID),
'posts_per_page' => 3
);
$relatedquery = new WP_Query( $relatedargs );
while($relatedquery->have_posts()){
$relatedquery->the_post();
$ID = get_the_ID();
?>
<div class="span3">
<?php
if(has_post_thumbnail()) {
$relatedthumbnail = wp_get_attachment_image_src( get_post_thumbnail_id($ID), 'medium', false);
$relatedthumbnail_large = wp_get_attachment_image_src( get_post_thumbnail_id($ID), 'full', false);
?>
<div class="hover_colour"><a href="https://wordpress.stackexchange.com/questions/117081/<?php echo $relatedthumbnail_large["0']; ?>" rel="prettyPhoto"><img src="<?php echo $relatedthumbnail['0']; ?>" alt="<?php the_title(); ?>" /></a>
</div>
<?php } ?>
<h6><a href="<?php the_permalink(); ?>"><span><?php the_title(); ?></span></a><br><i class="icon-time muted"></i> <?php echo get_the_time('j') . "https://wordpress.stackexchange.com/" . get_the_time('m') . "https://wordpress.stackexchange.com/" . get_the_time('Y') . ' '; ?> <i class="icon-comments muted"></i> <a href="<?php the_permalink(); ?>"> <?php comments_number(0 . __(' comments','textdomain'), 1 . __(' comment','textdomain'), '% ' . __('comments','textdomain')); ?></a></h6>
</div>
<?php }
wp_reset_postdata();
}
Then, in your theme, inside the loop, you can call the function wherever you want to display latest posts from the author of the current post:
<?php
if ( have_posts() ) {
while ( have_posts() ) {
the_post();
//some content goes here regarding the post itself!!!
//some content goes here regarding the post itself!!!
the_latest_author_posts($post);
}
}
?>