How to use the event aftersave?

I write in the model, but it is not invoked when saving data in the database.

public function aftersave ($ insert, $ changedattributes)
{
var_dump ("ooooooooo");
}

Here is my model:

& lt;? php
Namespace App \ Modules \ Userpanel \ Models \ Userpanel;
Use App \ Models \ DB_Table \ Tablename;
USE Yii \ Base \ Model;
USE Yii;
USE Yii \ Base \ EVENT;
USE Yii \ db \ ActiveRecord;
Class Form Extends Model
{
  Public $ user_id;
  Public Function Rules ()
  {
    Return [
      ['User_ID', 'Required'],
    ];
  }
Public Function Aftersave ($ Insert, $ ChangeDattributes)
  {
    Parent :: Aftersave ($ Insert, $ ChangeDattributes);
    var_dump ("ooooooooo");
  }
Public Function AddZakazdb ()
  {
    $ MODEL2 = new tablename ();
    $ model2- & gt; user_id = $ this- & gt; user_id;
    Return $ model2- & gt; save ();
  }
}

Answer 1, Authority 100%

You missed the parent method:

public function aftersave ($ insert, $ changedattributes) {
  Parent :: Aftersave ($ Insert, $ ChangeDattributes);
  // below your code
  var_dump ("ooooooooo");
}

Why? Because we convey to the parent method all the same parameters and launch it, and then we do everything you need.