为PHP搜索代码创建表单元素

Question

I have some code to sort search results by highest price or lowest price in Wordpress.

But I do not have a corresponding code for the form to make a selector for the code. Thank you

global $query_string;
if($_GET['orderby']=="highestprice") {  
    $args = array(
        'post_type' => 'property',
        'posts_per_page' => '-1',
        'meta_key' => 'nt_listprice',
        'orderby' => 'meta_value_num',
        'order' => 'DESC',
        'meta_query' => array(
            array(
                   'key' => 'nt_listprice'
                   )
         )
     );
} elseif($_GET['orderby']=="lowestprice") { 
    $args = array(
        'post_type' => 'property',
        'posts_per_page' => '-1',
        'meta_key' => 'nt_listprice',
        'orderby' => 'meta_value_num',
        'order' => 'ASC',
        'meta_query' => array(
            array(
                   'key' => 'nt_listprice'
                   )
         )
     );
} else {
    $args = array(          
        'post_type' => 'property',
        'posts_per_page' => '-1',
        'order'=>'DESC',
        'orderby'=> 'post_date'
    );
}

There is some sample Form code here

            <?php if ($nt_option["sp_location"] == "1"): ?>
                <div class="col-lg-2 col-md-2 col-sm-12 col-xs-12">
                    <select class="form-control select" name="locations">
                        <option value=""><?php if (isset($nt_option["s_location"])) {
                                echo $nt_option["s_location"];
                            } ?></option>
                        <?php $locations = get_terms('location'); ?>
                        <?php foreach ($locations as $location): ?>
                            <option value="<?php echo $location->slug; ?>"><?php echo $location->name; ?></option>
                        <?php endforeach; ?>
                    </select>
                </div>
            <?php endif; ?>