Essential XAML

Introduction: You have a collection of items and you want to display them as an expander group. Only one expander should be opened at a time.

Problem: There is no expander group in WPF such as panel for RadioButton, also you don't want to write custom code, only XAML.

Solution: Bind the collection of items to a ListBox. Create a DataTemplate to display each item as an expander. Bind the expander IsExpanded property to the ListBoxItem.IsSelected. Override the default ListBoxItem style so it wont visualize selected state.

Code Snippet:

<DataTemplate DataType="{x:Type local:Sign}">
    <Expander Padding="4"
              IsExpanded="{Binding RelativeSource={
                    RelativeSource Mode=FindAncestor, AncestorType={
                       x:Type ListBoxItem}}, Path=IsSelected}">

        <Expander.Header>
            <TextBlock Text="{Binding Name}" ... />
        </Expander.Header>
        <DockPanel LastChildFill="True">
            <Border DockPanel.Dock="Left" CornerRadius="16" BorderBrush="WhiteSmoke" Background="AliceBlue" BorderThickness="5" HorizontalAlignment="Center" VerticalAlignment="Center">
                <Image Source="{Binding Icon}" Width="90" Height="90" Stretch="Fill" />
            </Border>
            ...

        </DockPanel>                
    </Expander>
</DataTemplate>

<ListBox ItemsSource="{Binding Path=Signs}" />

* There is another solution, you can create a RadioButton control template to be displayed as expander

Download the code from here.