We have a form with three fields – where depending on the value of the first select field, we will show the other two form elements – one select field (the options depends on the value of the first select field) and one file upload field.

The issue is that when I upload a file the second select list value is resetting. Because managed_file form element is again calling an ajax function which overrides the value of my first ajax call

Code is below:

public function buildForm(array $form, FormStateInterface $form_state) {     $texts = array();     $text_values = db_query("SELECT text_id, title FROM `heritage_text_structure`")->fetchAll();     foreach($text_values AS $key => $value){         $texts[$value->text_id] = $value->title;     }     $form['text'] = array(         '#type' => 'select',         '#title' => $this->t('Select the heritage text'),         '#required' => TRUE,         '#options' => $texts,         '#default_value' => isset($form['text']['#default_value'])?$form['text']['#default_value']:null,         '#ajax' => array(             'event' => 'change',             'wrapper' => 'text-info',             'callback' => '::_ajax_text_callback',         ),     );     if(!empty($form_state->getTriggeringElement())) {         $description = '';         $text_id = $form_state->getTriggeringElement()['#value'];         $labels = db_query("SELECT level_labels FROM `heritage_text_structure` WHERE text_id = :text_id", array(':text_id' => $text_id))->fetchField();         $labels_array = explode(',', $labels);         $label_count = count($labels_array);         for($i=0; $i<count($labels_array); $i++){             if($i < $label_count-1)                 $description = $description.$labels_array[$i].', ';             else $description = $description.$labels_array[$i];         }         $description = $description.', Content, Language';         $csvCount = $label_count + 2;     }     $form['text_info'] = array(         '#type' => 'container',         '#prefix' => '<div id="text-info">',         '#suffix' => '</div>'     );     if(isset($text_id) && $text_id > 0){         $validators = array(             'file_validate_extensions' => array('csv '),         );         $form['text_info']['fieldset'] = array(             '#type' => 'fieldset',             '#title' => $this->t('Select the Target Source'),             '#description' => $this->t('Choose the source into which you are importing content'),          );         $sources = array();         $source_values = db_query("SELECT id, title FROM `heritage_source_nodes` WHERE text_id = :text_id", array('text_id' => $text_id))->fetchAll();         foreach($source_values AS $key => $value){             $sources[$value->id] = $value->title;         }         $form['text_info']['fieldset']['sources'] = array(             '#type' => 'select',             '#title' => $this->t('Select the Source to which content is imported'),             '#required' => TRUE,             '#options' => $sources,             '#default_value' => isset($form['text_info']['fieldset']['sources']['widget']['#default_value'])?$form['text_info']['fieldset']['sources']['widget']['#default_value']:null,         );         $form['text_info']['fieldset']['file'] = array(             '#type' => 'managed_file',             '#title' => t('Upload the Content in CSV format'),             '#size' => 20,             '#description' => t('CSV file (eg: '.$description.'). Please maintain the order of the fields.'),             '#upload_location' => 'public://file_uploads/',             '#upload_validators' => $validators,         );         $form['text_info']['fieldset']['csv_count'] = array(             '#type' => 'hidden',             '#value' => $csvCount,         );     }     $form['actions']['submit'] = array(         '#type' => 'submit',         '#value' => $this->t('Import Content'),     );     return $form; } /** * {@inheritdoc} Map content to the corresponding fields. */ public function submitForm(array &$form, FormStateInterface $form_state) {     $text = $form_state->getValue('text');     print("<pre>");print_r($form_state->getValue());exit; }  /** * Ajax callback function */ public function _ajax_text_callback(array $form, FormStateInterface $form_state) {     return $form['text_info']; }