Filter Members Directory by Member Type.

yzc_filter_md_by_type.php

<?php
/**
 * Get Field Options
 */
function yzc_get_xprofile_field_options( $field_id ) {
  
    // Get Field Data.
    $field = new BP_XProfile_Field( $field_id );
    // Get Select Box Options.
    $children = $field->get_children();
    
    //
    $options = wp_list_pluck( $children, 'name' );
    return $options;
}
/**
 * Add New Xprofile Field As new Filter.
 */
function yzc_add_new_members_directory_filter() {
        
    // Get Member Types
    $member_types = yz_get_member_types();

    if ( ! yz_is_member_types_active() || empty( $member_types ) ) {
        return false;
    }

    ?>

    <li id="members-type" class="last filter">
        <select id="members-type">
            <option value=""><?php _e( 'Member Type', 'youzer' );?></option>
            <?php foreach ( $member_types as $type ): ?>
                <?php 

                    if ( 'false' == $type['show_in_md'] ) {
                        continue;
                    }

                    // Make the id lowercase.
                    $type_id = isset( $type['id'] ) ? $type['id'] : yz_get_member_type_id( $type['singular'] );

                    // Get Type
                    $type_infos = bp_get_term_by( 'slug', $type_id, bp_get_member_type_tax_name() );
                    //$type_infos->count 
                    if ( ! isset ( $type_infos->count ) || $type_infos->count < 1 ) {
                        continue;
                    }

                ?>
                <option value="<?php echo $type_id; ?>"><?php echo $type['name']; ?></option>
            <?php endforeach; ?>
        </select>
    </li>

    <?php
}
add_action( 'bp_members_directory_member_sub_types', 'yzc_add_new_members_directory_filter' );
/**
 * Members Directory - Set Field Filter.
 */
function yzc_set_filter_by_xprofile_field( $loop ) {
   
    if ( bp_is_members_directory() && isset( $_POST['filter'] ) ) {
        $loop['member_type'] = $_POST['filter'];
    }
    return $loop;
}
add_filter( 'bp_after_has_members_parse_args', 'yzc_set_filter_by_xprofile_field', 9999 );