Set select box options in form_alter

Question

I have a select box named field_ee_project . I want to add the select box options dynamically on hook_form_alter .

What i have tried

---

    function gamodule_form_alter(&$form, FormStateInterface $form_state, $form_id) {
       //check whether the form is effort estimation
        if($form_id = 'node_effordestimation_form'){
            $form['field_ee_project']['und']['#options'] = effort_estimation_project_autoload();
        }
     }

    /*
     * Effort estimation project field select box
     */
    function effort_estimation_project_autoload(){
            $matches = array();
            $result = db_query("SELECT ga_id,name FROM ga_projects");
            $row = $result->fetchAll();
            $row = json_decode(json_encode($row), True);
            foreach ($row as $key => $value) {
                $matches[$value['name']] = $value['name'];
             }
            return $matches;
    }

But it is not working . Any idea ?

Answer 1

Try this it should work.

 function gamodule_form_alter(&$form, FormStateInterface $form_state, $form_id) {
   //check whether the form is effort estimation
    if($form_id = 'node_effordestimation_form'){
        $form['field_ee_project']['widget']['#options']  = effort_estimation_project_autoload();
    }
 }

function effort_estimation_project_autoload(){
                $matches = array();
                $result = db_query("SELECT ga_id,name FROM ga_projects");
                $row = $result->fetchAll();
                $row = json_decode(json_encode($row), True);
                foreach ($row as $key => $value) {
                    $matches[$key] = $value['name'];
                 }
                return $matches;
        }

Answer 2

The Field Type API are more strict in Drupal 8 so that Web Services and Forms follow the same validation path. This is not always the behavior that we want.

Looking at your question again, I think that using an allowed values callback on the field would work as well.

I provided some alternatives based on the restrictions that core places on list fields below #1 as well in case the following doesn't work as intended. These could be useful for other people doing similar things.

#1: Try to use allowed values callback for the field instead

Set an allowed_values_callback for the list field.

function gamodule_allowed_values_callback(FieldStorageDefinitionInterface $definition, FieldableEntityInterface $entity = NULL, &$cacheable = TRUE) {
  // @todo make this a bit more conditional based on the parameters above.
  $result = db_query("SELECT ga_id,name FROM ga_projects");
  $row = $result->fetchAll();
  $row = json_decode(json_encode($row), True);
  foreach ($row as $key => $value) {
    $matches[$key] = $value['name'];
  }
  return $matches;
}

Note that the documentation for callback_allowed_values_callback mentions using opt groups, but this functionality has a bug and is broken in 8.

#2: Migrate list field to text field

Make a Select list Field Widget for text fields. Migrate your data over.

Risks

• A lot of work to re-architect.
• May confuse a development team inheriting the site.

#3: Override the AllowedValues constraint plugin

Use hook_validation_constraint_alter to provide your own Constraint plugin (see Symfony 2 Constraint documentation).

Risks

• Site is incompatible with a couple of contrib modules doing the same thing (select_or_other, cck_select_other).

#4: Make sure all possible allowed values are in the list field

Don't use a custom table to store allowed values. Set the allowed values in list field configuration. Write a field widget plugin.

Write your own Field Widget that restricts options based on some other parameter like your query.

#5: Override Core handling of list field plugins with your own implementation

Use hook_field_info_alter to not use Core code at all. Write your own List Field Type plugin with a better Options or Allowed Values implementation.

Risks

• May confuse a development team inheriting the site.
• All list fields now behave this way.

Answer 3

To set options dynamically use allowed_values_function in field instance definition configuration.

Refer : https://chromatichq.com/insights/dynamic-default-and-allowed-values-list-fields-drupal-8/