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Ever wanted to have a dynamic option list in your Webform select widget ( checkbox, radiobutton, dropdown ) ?

Well, I wanted to load a dynamic list of dates in a Webform and display them as checkboxes. I faced this problem when I was developing a training website where each training class would have different training dates.

So let's start and build our dynamic select option list.

In order to achieve this you need to do the following steps:

1. Add a select widget to your Webform

2. Create a custom Webform module ( webform_custom ) with the following files.

• webform_custom.info – as the name suggest contains the info of the module

name = Webform Custom
description = Provides custom functionality for the Webform
core = 6.x
project = "webform_custom"
package = Other

• webform_custom.module – this file will contain the code that will generate our dynamic options list, for now just keep this file empty

3. Active you custom module from Administer → Site building → Modules

4. The following hook adds another item for “Load a pre-built option list” menu in Webform's select form component. This hook will go into the module file:

function webform_custom_webform_select_options_info()

{

     $items = array();

     if (function_exists('_webform_get_dates'))
     {

          $items['training_dates'] = array(

       'title' => t('Training class dates'),

        'options callback' => '_webform_get_dates',

        );

   }

   return $items;

}

The result of the above function will add the following item in the select form component drop-down:

As you have noted already we still do not have the data yet. No worries!!

The following code fetches the data from the database and returns a list of all dates for a particular node/training class but you can return whatever you want as long as its an array:

function _webform_get_dates()

{

   $dates = array();

   $node_id = arg(1);

   $select = db_query(db_rewrite_sql("

              SELECT t.nid, t.field_training_date_value as tdate

              FROM {content_type_training_class} c, {node} n

              WHERE c.nid='$node_id'

              and c.nid=n.nid

              ORDER BY field_training_date_value"));

    while ($date = db_fetch_object($select)) {

     $td = $date->tdate;

     $dates[$td] = $td;

   }

  return $dates;

}

5. Now go back to the Webform select form component and choose the 'Training class dates' option from the “Load a pre-built option list” dropdown and save the field.

You can do a lot of customization with these hooks, which may not be possible to do via Drupal's admin interface. See the full list of Webform hooks here.

That's it folks!!

Filed under: PHP