List all posts in a category with query_post() function

Question

I'm a C programmer, konw little about PHP. I built a Blog with wordpress.

Yestoday, I try to create the page www.abc.com/server, this page would list all posts which belong to server category.

I found some useful information in wordpress document and Google

I created a template like this:

<?php
 /*
  * Template name: list_catetory
  */
?>

<?php get_header(); ?>
    ...
    <?php 
    query_posts( 'cat_name = $pagename' );
    if(have_posts()) : while(have_posts()) : the_post(); ?>
    <div class="post-list"  id="post-<?php the_ID(); ?>">
        <h2>
             <a href="<?php the_permalink() ?>" title=""><?php the_title(); ?></a>
             ....
        </h2>
     </div>

     <?php endwhile; ?>
     <?php wp_reset_query(); ?>
     ...
<?php get_footer(); ?>

I create a page named server with this template.

then I open this page, I found this page list all post.

Why it lists all post, not only list the posts belong to server category

Answer 1

There are two issues here:

1. The use of query_posts()
2. Undefined $pagename variable

I assume that you want to use the page slug as the string passed for the category parameter in the query arguments array? You can get that via $post->post_name, like so:

global $post;
$page_slug = $post->post_name;

Then, to pass that as a query parameter, you would pass it as 'category_name'.

Finally, you want to output a custom query, via WP_Query(), rather than call query_posts():

// Globalize $post
global $post;
// Custom query args array
$category_query_args = array(
    'category_name' => $post->post_name
);
// Instantiate category query
$category_query = new WP_Query( $category_query_args );

Then, you can loop through your custom query like so:

// Open category query loop
if ( $category_query->have_posts() ) : while ( $category_query->have_posts() ) : $category_query->the_post();
    ?>

    <div class="post-list"  id="post-<?php the_ID(); ?>">
        <h2>
             <a href="<?php the_permalink() ?>" title=""><?php the_title(); ?></a>
             ....
        </h2>
     </div>

    <?php
// Close category query loop
endwhile; endif;
// Reset $post data
wp_reset_postdata();