Ok yet I answered another one of my own questions. I was able to create the drop down filter that retrieves the child terms of the current taxonomy page being viewed. For anyone interested in the solution, here it is ---
First I had to create in my functions.php file a walker class --
class SH_Walker_TaxonomyDropdown extends Walker_CategoryDropdown{
function start_el(&$output, $category, $depth, $args) {
$pad = str_repeat(' ', $depth * 2);
$cat_name = apply_filters('list_cats', $category->name, $category);
if( !isset($args['value']) ){
$args['value'] = ( $category->taxonomy != 'category' ? 'slug' : 'id' );
}
$value = ($args['value']=='slug' ? $category->slug : $category->term_id );
$output .= "\t<option class=\"level-$depth\" data-filter-value=\".".$value."\"";
if ( $value === (string) $args['selected'] ){
$output .= ' selected="selected"';
}
$output .= '>';
$output .= $pad.$cat_name;
if ( $args['show_count'] )
$output .= ' ('. $category->count .')';
$output .= "</option>\n";
}
}
Then I placed this code in my sidebar --
<?php
//first get the current term
$current_term = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) );
//then set the args for wp_dropdown_categories
$args = array(
'walker'=> new SH_Walker_TaxonomyDropdown(),
'value'=>'slug',
'child_of' => $current_term->term_id,
'taxonomy' => $current_term->taxonomy,
'hide_empty' => 0,
'hierarchical' => true,
'depth' => 2,
'title_li' => '',
'id' => 'filter-select',
'class' => 'filter option-set',
'show_option_all' => All,
'hide_if_empty' => true
);
wp_dropdown_categories( $args );
?>