Silverlight MVVM ListBoxItem IsSelected

I have a collection of ViewModels bound to a ListBox. I am trying to bind the IsSelected properties of each together. In WPF it works by setting the style:

<Style TargetType="{x:Type ListBoxItem}">
    <Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}" />
</Style>

This does not work in Silverlight. How can I accomplish this?

From stackoverflow

• In Silverlight, you are not able to create "global" styles, that is, styles that modify all controls of a certain type. Your style needs a key, and your control needs to reference it.

  Also, TargetType simply needs the control type name. Silverlight does not support the x:Type extension.

  ib.

• Here's how i do it:

  <ListBox.ItemTemplate>
      <DataTemplate>
  ...
  <CheckBox VerticalAlignment="Top" HorizontalAlignment="Left"
            x:Name="CheckBox1" IsChecked="True" Grid.Row="0">
      <inf:BindingHelper.Binding>
          <inf:BindingProperties TargetProperty="Visibility" SourceProperty="IsSelected"
              Converter="{StaticResource VisibilityConverter}"
              RelativeSourceAncestorType="ListBoxItem" />
      </inf:BindingHelper.Binding>
  </CheckBox>
  ...
      </DataTemplate>
  </ListBox.ItemTemplate>
  

  You need to do relative binding, which doesn't exist in Silverlight unfortunately... BindingHelper is a helper class which overcomes this limitation (search for "relative binding in silverlight" to find it).