title: Xamarin Form picker using EventToCommandBahavior
body: <p>I have a custom picker. I need to call an API on selection changed of the picker and the implementation must be only in MVVM. DistanceDropdown is the x:Name of picker.</p>
  <pre><code>&lt;custom:MyPicker.Behaviors&gt;
               &lt;behaviors:EventToCommandBehavior EventName=&quot;SelectedIndexChanged&quot;
                                                 Command=&quot;{Binding Path=BindingContext.DistanceChangedCommand,Source={x:Reference DistanceDropdown}}&quot;&gt;&lt;/behaviors:EventToCommandBehavior&gt;
     &lt;/ccustom:MyPicker.Behaviors&gt;
  </code></pre>
  <p>And DistanceChangedCommand has a method</p>
  <pre><code>DistanceChangedCommand = new Command&lt;object&gt;(async (x) =&gt; await DistanceChangedAction(x as SelectionChangedEventArgs));
  </code></pre>
  <p>The method gets hit, but the args are null</p>
  <pre><code>private async Task DistanceChangedAction(SelectionChangedEventArgs selectionChangedEventArgs)
          {
              await Task.CompletedTask;
          }
  </code></pre>
  <p>What am I going wrong? I have also tried with <code>CommandParameter={Binding}</code>.</p>