Eventually the solution I used was this. Upon change of Dropdown A I have an ajax function request tha re-populated Downdown B with the filtered options based on the selection in Dropdown A.
See the ajax jquery script…
countryFilter = function () {
var countryClass=".dealer-country select",
dealerClass=".dealer-name select";
$(countryClass).change(function(){
var countrySelect = $(this),
country = countrySelect.val(),
dealerSelect = countrySelect.parents('form').find(dealerClass);
if(country != "default") {
$.ajax({
type: 'POST',
url: '<?php echo admin_url('admin-ajax.php'); ?>',
data: { dealerCountry : country, action: 'get_dealer_name' },
success: function(data){
dealerSelect.empty();
var options = $.parseJSON(data);
for(i=0;i<options.length;i++){
dealerSelect.append('<option value="'+options[i].value+'">'+options[i].text+'</option>');
}
dealerSelect.removeAttr('disabled');
}
});
}
});
}
Which I fired using…
$(document).ready(function () {
countryFilter();
});
$(document).bind('gform_post_render', function(event, form_id){
if(form_id == 3) {
countryFilter();
}
});
I then trimed my original functions to…
// Dropdown A - Dealer Country
add_filter("gform_pre_render", "dropdown_dealer_country");
add_filter("gform_admin_pre_render", "dropdown_dealer_country");
function dropdown_dealer_country($form){
if($form["id"] != 3)
return $form;
$terms = get_terms("dealer-country");
$items = array();
$items[] = array( "text" => __('Select country...','theme'), "value" => 'default' );
foreach($terms as $term)
$items[] = array( "text" => $term->name, "value" => $term->slug );
foreach($form["fields"] as &$field){
if($field["id"] == 6 ){
$field["cssClass"] = 'dealer-country';
$field["choices"] = $items;
}
}
return $form;
}
// Dropdown B - Dealer Name
add_filter("gform_pre_render", "dropdown_dealer_name");
add_filter("gform_admin_pre_render", "dropdown_dealer_name");
function dropdown_dealer_name($form){
if($form["id"] != 3)
return $form;
$items = array();
$items[] = array( "text" => __('Select dealer...','theme'), "value" => 'default' );
foreach($form["fields"] as &$field){
if($field["id"] == 7){
$field["cssClass"] = 'dealer-name';
$field["choices"] = $items;
}
}
return $form;
}
Then the finishing touch is the function which also goes in the functions.php – this is called by the ajax request…
function get_dealer_name_fn(){
$dealerCountry = $_POST['dealerCountry'];
$dealers = get_posts(array(
"post_type" => "dealer",
"dealer-country" => $dealerCountry,
"post_status" => "publish",
"orderby" => "title",
"order" => "ASC",
"posts_per_page" => -1
));
$items = array();
$items[] = array( "text" => __('Select dealer...','theme'), "value" => 'default' );
foreach($dealers as $dealer){
$items[] = array( "text" => $dealer->post_title, "value" => $dealer->post_title );
}
echo json_encode($items);
die;
}
add_action('wp_ajax_get_dealer_name', 'get_dealer_name_fn');
add_action('wp_ajax_nopriv_get_dealer_name', 'get_dealer_name_fn');