How to take options from form fields and turn them in to links?

Question

I have a form in WordPress with options when clicked they retrieve a filtered posts. I want to take the options from the form and place it like normal links. Can this be done? Thank You all in advance :)

<form action="" method="get" id="filter">
<select id="sort_by" name="sort_by" onchange="this.form.submit()">
<option value="most_recent"<?php if( !$_GET['sort_by'] || $_GET['sort_by'] == 'most_recent' ) echo " selected"; ?>><?php print   
    __('Most Recent', 'bo'); ?></option>
<option value="most_favorites"<?php if( $_GET['sort_by'] == 'most_favorites' ) echo " selected"; ?>><?php print __('Most Favorites', 'bo'); ?></option>
<option value="most_viewed"<?php if( $_GET['sort_by'] == 'most_viewed' ) echo " selected"; ?>><?php print __('Most Viewed', 'bo'); ?></option>
<option value="most_commented"<?php if( $_GET['sort_by'] == 'most_commented' ) echo " selected"; ?>><?php print __('Most Commented', 'bo'); ?></option>
</select>
</form>

Answer 1

Yes. First of all, to be able to highlight the current sorting method, we attempt to retrieve if the GET variable sort_by occurs in the url:

<?php switch ($_GET["sort_by"]) {
    case 'most_recent':
        $active = 'most_recent';
        break;
    case 'most_favourite':
        $active = 'most_favourite';
        break;
    case 'most_viewed':
        $active = 'most_viewed';
        break;
    default:
        // However you sort by default
        $active = 'most_recent';
}?>

If a valid sort order is present, $active is set to this. Otherwise it is set to the default order. We shall use this later.

Next we retrieve the url, then remove the sort_by GET variable. This allows us to manually add it later to the links without having duplicates.

<?php
//Retrieve _GET variables
$params = $_GET;

//Retrieve 'sort_by' variable
unset($params['sort_by']);;

//Rebuild url without 'sort_by' variable
$url = get_pagenum_link();
$url = strtok($url, '?');
$url =$url.'?'.http_build_query($params);
?>

Finally we construct the links. Here I've used $active to conditionally add the 'active' class when that sort method is currently being used.

<ul>
    <li <?php if($active == "most_recent"): ?> class="active"<? endif ?>><a href="http://<?php echo $url ?>&sort_by=most_recent">Most recent </a></li>
    <li <?php if($active == "most_favourite"): ?> class="active"<? endif ?>><a  href="http://<?php echo $url ?>&sort_by=most_favourite">Most favourite</a></li>
    <li <?php if($active == "most_viewed"): ?> class="active"<? endif ?>><a href="http://<?php echo $url ?>&sort_by=most_viewed">Most viewed </a></li>
</ul>

All the above code should appear wherever you want the links to occur. You can put it inside your functions.php, inside a function, however, and then call that function wherever you want the links to appear.

Hope this helps :D