Search breaks when querying main loop for category

Question

In my theme I provide an option for users to set a 'blog category' that queries and displays only posts from that category on index.php using WP_Query:

$shortname = get_option('of_shortname');
$cat_option = get_option($shortname.'_cats_in_blog');
$catid = get_cat_ID($cat_option);
$paged = get_query_var( 'paged' ) ? get_query_var( 'paged' ) : 1;
$args = array(
   'cat' => $catid,
   'paged' => $paged
);

$query = new WP_Query( $args );

// Queries fine, but search stops working       
while ( $query->have_posts() ) : $query->the_post();

// Loop stuff here

endwhile;

This works well, but the search widget breaks. I have also tried using query_posts but that has the opposite effect; the queried category isn't shown but the search still functions. Here's that code:

$shortname = get_option('of_shortname');
$cat_option = get_option($shortname.'_cats_in_blog');
$catid = get_cat_ID($cat_option);

// Search is working, querying is not
global $query_string; // required
$posts = query_posts($query_string.'&posts_per_page=3&cat=$catid');

while ( $query->have_posts() ) : $query->the_post();

// Loop stuff here

endwhile;

I checked the $catid variable and it is returning what is should. Am I querying the wrong way or in the wrong place? Any help is greatly appreciated, thanks in advance.

Answer 1

For your second example, I think you're initiating your Loop incorrectly. You're declaring $query, which hasn't been globalized?

// Search is working, querying is not
global $query_string; // required
$posts = query_posts($query_string.'&posts_per_page=3&cat=$catid');

while ( $query->have_posts() ) : $query->the_post();

Try omitting $query from your Loop initiation?

// Search is working, querying is not
global $query_string; // required
$posts = query_posts($query_string.'&posts_per_page=3&cat=$catid');

while ( have_posts() ) : the_post();

...and see if that makes a difference?

For the first example, what does "the search Widget breaks" mean?

EDIT

Wow, I completely overlooked this: you're passing your variable as a string:

$posts = query_posts($query_string.'&posts_per_page=3&cat=$catid');

Try this instead:

$posts = query_posts( $query_string . '&posts_per_page=3&cat=' . $catid );

...so that your $catid gets parsed properly.