title: WPF ComboBox Mvvm binding
body: <p>I am trying to get selected value from list into the command. Is there simple way to bind commandparameter to selected item?</p>
  
  <pre><code>&lt;ComboBox HorizontalAlignment="Left" Margin="-56,10,0,0" VerticalAlignment="Top" Width="120" SelectedIndex="0" ItemsSource="{Binding Time}"&gt;
          &lt;i:Interaction.Triggers&gt;
              &lt;i:EventTrigger EventName="Loaded"&gt;
                  &lt;i:InvokeCommandAction Command="{Binding TestCommand}" CommandParameter="{Binding }"&gt;&lt;/i:InvokeCommandAction&gt;
              &lt;/i:EventTrigger&gt;
              &lt;i:EventTrigger EventName="SelectionChanged"&gt;
                  &lt;i:InvokeCommandAction Command="{Binding TestCommand}" CommandParameter="{Binding }"&gt;&lt;/i:InvokeCommandAction&gt;
              &lt;/i:EventTrigger&gt;
          &lt;/i:Interaction.Triggers&gt;
      &lt;/ComboBox&gt;
  </code></pre>
  
  <p>When i tried something like </p>
  
  <pre><code>                &lt;i:EventTrigger EventName="SelectionChanged"&gt;
                  &lt;i:InvokeCommandAction Command="{Binding TestCommand}" CommandParameter="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ComboBox}},Path=SelectionBoxItem}"&gt;&lt;/i:InvokeCommandAction&gt;
              &lt;/i:EventTrigger&gt;
  </code></pre>
  
  <p>it's strange stuck why?</p>