title: AngularDart Components Dropdown Selects selectionChange event
body: <p>I'm using <code>material-dropdown-select</code> component, but I didn't find the way to trigger the event when the user changes the  selection.</p>
  
  <p>(on selection change ??)</p>
  
  <pre><code>&lt;material-dropdown-select class="psDropDown" dir="rtl"
                      [buttonText]="dropDownSelectLabel" 
                      [selection]="singleSelectModel" 
                      [options]="lookUpOptions"
                      &gt;&lt;/material-dropdown-select&gt;
  </code></pre>
  
  <p>How can I react to a selection change event</p>