How can I sort my loop based on meta data, using a form?

Question

I've created a custom post type called 'properties' with custom meta boxes of 'price' and 'rooms'.

I have a custom loop-property-archive.php to display the properties.

What I would love to have is a method to sort the properties based on the meta data from those two meta boxes. Ideally I would have a drop-down called 'sort by', with the options of 'price asc.', 'price desc.', 'rooms asc.', and 'rooms desc.'. When the user selects an option the page is re-sorted.

I can currently query by custom taxonomies, which creates a URL like: mysite.com/?post_type=properties&area=high-ridge&university=birmingham. I need to be able to filter that page or any other combination of area and university. Therefore building individual templates with custom queries is out of the question.

I tested out appending meta_key=_price&orderby=meta_value to the URL but that doesn't work. Any ideas why?

I'm open to server or client side suggestions. Server may be better because if there is pagination involved I think that would be handled better. Obviously client side has the advantage of no page refreshes though.

Thanks!

Answer 1

This should help: http://wordpress.org/support/topic/custom-select-query-sort-by-meta-value-within-category (look for the posts from user t31os)

Also this: http://codex.wordpress.org/Template_Tags/query_posts#Passing_variables_to_query_posts