title: Event handling in PrimeNG
body: <p>Tell me, please, where to find examples of event processing in PrimeNG.
  Well, I do not know what to write instead of XXX. </p>
  
  <pre><code>&lt;p-dropdown (onChange)="onChangeCity(XXX)"...&gt;&lt;/p-dropdown&gt;
  ...
  ...
  onChangeCity(XXX){
  ...
  }
  </code></pre>