Trying to create plugin for results per page – Woocommerce

Woocommerce actually has support for this through its actions and filters. Below is what has been updated and I feel like it is close but I cannot figure out how to apply the changes, say I click on 24, how should I go about getting the page to reload and apply the users selection. Does what I have below seem like I am on the right path? Anyone able to chime in on how to apply the users selection to the page?

Updated code:

function woocommerce_sortby_page () {
  $value = $_POST['value'];
  add_filter('loop_shop_per_page', create_function('$cols', 'return $value;'));
}

function woocommerce_catalog_page_ordering() {
?>
<form action='<?php echo $_SERVER['PHP_SELF']; ?>' method='post'>
<select name="woocommerce-sort-by-columns">
<option value="12">12</option>
<option value="16">16</option>
<option value="20" selected>20</option>
<option value="24">24</option>
<option value="28">28</option>
</select>
</form>
<?php
} 

add_action( 'woocommerce_pagination', 'woocommerce_catalog_page_ordering', 20 );

excuse me if this is a laughable question but where do I put the array key ‘results’?

Just to make sure I am paying attention here is where I am with it

function woocommerce_sortby_page () {
  $value = $_POST['woocommerce-sort-by-columns'];
  add_filter('loop_shop_per_page', create_function('$cols', 'return $value;'));
}

function woocommerce_catalog_page_ordering() {
?>
<form action="" method="post" name="results">
<select name="woocommerce-sort-by-columns" onchange="document.forms['results'].submit();">
<option value="12">12</option>
<option value="16">16</option>
<option value="20" selected>20</option>
<option value="24">24</option>
<option value="28">28</option>
</select>
</form>
<?php
} 

add_action( 'woocommerce_pagination', 'woocommerce_catalog_page_ordering', 20 );

Wow, after tons of exploring on the internet, a full nights sleep and a cup of coffee (make that two cups) I finally got it!! Thanks so much for your help!

Now I only face two small problems:
1) how do I get the number of results per page that the user sets display through all pages? Currently I can select 4 products per page and the page I am on adjusts but when I click on next page it goes back to default.

2) This isnt as big of a deal but is there anyway to make the option the user chooses the ‘selected’ one when the page refreshes? In other words when I click on 24 results per page and hit submit, when the page reloads with the adjustments the dropbox still has the first option as the selected tag.

here is what is currently working:

function woocommerce_catalog_page_ordering() {
?>
<form action="" method="POST" name="results">
<select name="woocommerce-sort-by-columns" id="woocommerce-sort-by-columns" class="sortby">
<?php
			$shopCatalog_orderby = apply_filters('woocommerce_sortby_page', array(
			    ''       => __('Results per page', 'woocommerce'),
				'4' 	=> __('4 per page', 'woocommerce'),
				'12' 		=> __('12 per page', 'woocommerce'),
				'24' 		=> __('24 per page', 'woocommerce'),
			));

			foreach ( $shopCatalog_orderby as $sort_id => $sort_name )
				echo '<option value="' . $sort_id . '" ' . selected( $_SESSION['sortby'], $sort_id, false ) . '>' . $sort_name . '</option>';
		?>
</select>
<input name="submitbutton" type="submit" value="submit" />
</form>
<?php

} 

function dl_sort_by_page() {
global $dl_page_value;
  $dl_page_value = $_POST['woocommerce-sort-by-columns'];

  return $dl_page_value;
}

add_filter('loop_shop_per_page','dl_sort_by_page');
add_action( 'woocommerce_pagination', 'woocommerce_catalog_page_ordering', 20 );

Now im going to make that second cup o’joe 😀

Wow thanks for that head start and thanks so much for your help! Cheers