* Collection: + count and populate from selection

Collection.php

@@ -34,7 +34,7 @@ class Collection extends Component
  /**
  * @var array of models
  */
- public $models;
+ public $models = [];
 
  /**
  * @var string the name of the form. Sets automatically on [[set()]]
@@ -202,6 +202,11 @@ public function load ($data = null) {
  if (!$is_bulk) {
  $data = [$data];
  }
+ } else if ($data['selection']) {
+ foreach ($data['selection'] as $id) {
+ $res[$id] = compact('id');
+ }
+ $data = $res;
  }
  } elseif ($data instanceof \Closure) {
  $data = call_user_func($data, $this->model, $this->formName);
@@ -446,6 +451,10 @@ public function getFirstError () {
  return false;
  }
 
+ public function count()
+ {
+ return is_array($this->models) ? count($this->models) : 0;
+ }
 
  public function validate ($attributes = null) {
  if (!$this->beforeValidate()) {