wp-dynamic-values-for-dropdown.php

<?php 

/**
* Dynamically populate the values for Gravity Form drop downs
*
* @param array $form
* @return mixed
* @access public
*/
function az_gravityforms_dynamic_dropdown_values( $form ) {

	$registered_classes = array( 'dynamic-values-partners' );

	foreach( $form['fields'] as &$field ) {

		// Get array of all CSS classes of the field
		$field_classes = explode( ' ', $field['cssClass'] );

		// Find a match in CSS class setting
		$matched_css_classes = array_intersect( $registered_classes, $field_classes );

		// Ignore this hook if not a drop down with the appropriate class
		if( $field['type'] != 'select' || !empty( $matched_css_classes ) === FALSE ) {
			continue;
		}

		$choices = array();
		$already_added = array();

		// Process the match
		switch( array_pop( $matched_css_classes ) ) {

			// Load a dropdown with the list of all partners
			case 'dynamic-values-partners':

			// Get all published partners
			$params = array(
				'post_type' => 'partners',
				'post_status' => 'publish',
				'posts_per_page' => -1,
				'orderby' => 'meta_value',
				'order' => 'ASC',
				'meta_key' => 'partner_name'
			);
		
			$partners = get_posts( $params );
			
			$choices[] = array( 'text' => '-- None --', 'value' => ' ' );
			$choices[] = array( 'text' => '-- Other --', 'value' => 'Other' );
			
			foreach( $partners as $partner ) {
				$partner_name = get_field( 'partner_name', $partner->ID );
				if ( !isset( $already_added[ $partner_name ] ) ) {
					$choices[] = array( 'text' => $partner_name, 'value' => $partner_name );
					$already_added[ $partner_name ] = $partner_name;
				}
			}
		
			break;

		}

		$field['choices'] = $choices;

	}

	return $form;
	
}

// Implement pre-render, pre-validation, pre-submission filter and admin pre-render hooks
add_filter( 'gform_pre_render', 'az_gravityforms_dynamic_dropdown_values' );
add_filter( 'gform_pre_validation', 'az_gravityforms_dynamic_dropdown_values' );
add_filter( 'gform_pre_submission_filter', 'az_gravityforms_dynamic_dropdown_values' );
add_filter( 'gform_admin_pre_render', 'az_gravityforms_dynamic_dropdown_values' );