I found the solution…
My functions page now looks like:
<?php
class dropdown extends Walker_CategoryDropdown {
function start_el(&$output, $category, $depth, $args) {
$pad = str_repeat(' ', $depth * 3);
$cat_name = apply_filters( 'list_cats', $category->name, $category );
$output .= "\t<option class=\"level-$depth\" value=\"".$category->slug."\"";
$output .= '>';
$output .= $pad.$cat_name;
if ( $args['show_count'] )
$output .= ' ('. $category->count .')';
if ( $args['show_last_update'] ) {
$format="Y-m-d";
$output .= ' ' . gmdate($format, $category->last_update_timestamp);
}
$output .= "</option>\n";
}
}
?>
My form now looks like:
<form method="get" id="searchform" action="<?php echo home_url(); ?>">
<input type="text" onclick="this.value="";" onfocus="this.select()" onblur="this.value=!this.value?'Product Search...':this.value;" value="Product Search..." name="s" id="s" class="left" />
<input type="image" src="https://wordpress.stackexchange.com/questions/50438/<?php bloginfo("template_directory') ?>/images/icosearch.png" id="searchsubmit" value=""/>
<?php
wp_dropdown_categories(
array(
'child_of' => 426,
'class' => 'styled',
'id' => 'make',
'name' => 'make',
'show_option_all' => 'Make...',
'taxonomy' => 'product_cat',
'walker' => new dropdown
))
?>
<?php
wp_dropdown_categories(
array(
'child_of' => 427,
'class' => 'styled',
'id' => 'model',
'name' => 'model',
'show_option_all' => 'Model...',
'taxonomy' => 'product_cat',
'walker' => new dropdown
))
?>
</form>
My search page now looks like:
<?php
$tmp[]=$_GET["model"];
$tmp[]=$_GET["make"];
$product_cat=array();
foreach($tmp as $v) {
if($v!="0")
$product_cat[]=$v;
}
if(count($product_cat)>0) {
$product_cat="&product_cat=".implode(",",$product_cat);
}
else {
$product_cat="";
}
$query=query_posts("s=$text".$product_cat);
$count =count($query);
if ($count == 0) {
echo 'No Results';
}
elseif ($count == 1) {
echo ''.$count.' Result';
}
else {
echo ''.$count.' Results';
}
?>