title: RelayCommand with parameters
body: <p>I am using the MVVM Light toolkit in my application and trying to learn about passing a command.
  I have the following XAML code snippet:</p>
  
  <pre><code>&lt;s:ScatterView x:Name="swPicture" ItemsSource="{Binding Pictures}" ItemTemplate="{StaticResource Scatter_Thumbnail}"/&gt;
      &lt;Button Content="Info" Width="40" Height="40"
                           Command="{Binding GetInfoCommand}"
                             Grid.Row="0" HorizontalAlignment="Left"/&gt;
  </code></pre>
  
  <p>Element swPicture contains items source coming from Pictures collection. As a test only for the time being I just have 1 single picture.</p>
  
  <p>How can I pass as a parameter to the command, the single first picture from the Pictures which is in my swPicture Element ?</p>
  
  <p>For the time being I am able to trigger the single command without parameter with following command handler in the model as defined bellow:</p>
  
  <pre><code>GetInfoCommand = new RelayCommand&lt;Picture&gt;(
              action=&gt;
                  {
                      GetMetaData();
                  },
                  g=&gt;true); //Execute method
  </code></pre>
  
  <p>The idea is that I need to pass the first Picture from the collection as a parameter to my command in order to pass it to GetMetaData which will have accept this parameter</p>
  
  <p>How can I update my XAML code and the command in order to make it work?</p>