--- /dev/null
+<?php
+
+namespace Drupal\views_ui;
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Form controller for the Views duplicate form.
+ */
+class ViewDuplicateForm extends ViewFormBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function prepareEntity() {
+ // Do not prepare the entity while it is being added.
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function form(array $form, FormStateInterface $form_state) {
+ parent::form($form, $form_state);
+
+ $form['#title'] = $this->t('Duplicate of @label', ['@label' => $this->entity->label()]);
+
+ $form['label'] = [
+ '#type' => 'textfield',
+ '#title' => $this->t('View name'),
+ '#required' => TRUE,
+ '#size' => 32,
+ '#maxlength' => 255,
+ '#default_value' => $this->t('Duplicate of @label', ['@label' => $this->entity->label()]),
+ ];
+ $form['id'] = [
+ '#type' => 'machine_name',
+ '#maxlength' => 128,
+ '#machine_name' => [
+ 'exists' => '\Drupal\views\Views::getView',
+ 'source' => ['label'],
+ ],
+ '#default_value' => '',
+ '#description' => $this->t('A unique machine-readable name for this View. It must only contain lowercase letters, numbers, and underscores.'),
+ ];
+
+ return $form;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function actions(array $form, FormStateInterface $form_state) {
+ $actions['submit'] = [
+ '#type' => 'submit',
+ '#value' => $this->t('Duplicate'),
+ ];
+ return $actions;
+ }
+
+ /**
+ * Form submission handler for the 'clone' action.
+ *
+ * @param array $form
+ * An associative array containing the structure of the form.
+ * @param \Drupal\Core\Form\FormStateInterface $form_state
+ * A reference to a keyed array containing the current state of the form.
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {
+ $this->entity = $this->entity->createDuplicate();
+ $this->entity->set('label', $form_state->getValue('label'));
+ $this->entity->set('id', $form_state->getValue('id'));
+ $this->entity->save();
+
+ // Redirect the user to the view admin form.
+ $form_state->setRedirectUrl($this->entity->urlInfo('edit-form'));
+ }
+
+}