How to get RadioButtons to work like ComboBox in MVVM pattern?

Question

In the following code, the user selects a customer from the ComboBox and that customer's information is displayed in the box.

Now I also want to get RadioButtons to work with the same functionality. I've got the RadioButtons to display the ObservableCollection of Customers, but how can I get the IsChecked to work, i.e. what is the equivalent of SelectedItem for RadioButtons?

XAML:

<Window.Resources>

    <DataTemplate x:Key="CustomerShowTemplate">
        <Border CornerRadius="5" 
                Background="#eee" 
                Padding="5" 
                HorizontalAlignment="Left">
            <StackPanel>
                <StackPanel Orientation="Horizontal">
                    <TextBlock FontSize="14" FontWeight="Bold" Text="{Binding FirstName}"/>
                    <TextBlock Text=" "/>
                    <TextBlock FontSize="14" FontWeight="Bold" Text="{Binding LastName}"/>
                </StackPanel>
                <TextBlock Text="{Binding Path=HireDate, 
                    StringFormat='Hired on {0:MMM dd, yyyy}'}"/>
            </StackPanel>
        </Border>
    </DataTemplate>

    <DataTemplate x:Key="CustomerComboBoxTemplate">
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="{Binding FirstName}"/>
            <TextBlock Text=" "/>
            <TextBlock Text="{Binding LastName}"/>
        </StackPanel>
    </DataTemplate>

    <DataTemplate x:Key="CustomerRadioButtonTemplate">
        <RadioButton GroupName="CustomerRadioButtonGroup" 
            IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsSelected}">
            <TextBlock Text="{Binding LastName}"/>
        </RadioButton>
    </DataTemplate>

</Window.Resources>

<DockPanel LastChildFill="False" Margin="10">

    <ContentControl 
        DockPanel.Dock="Top"
        Margin="0 0 0 10"
        Content="{Binding SelectedCustomer}" 
        ContentTemplate="{StaticResource CustomerShowTemplate}"/>

    <StackPanel 
        DockPanel.Dock="Top"
        Margin="0 0 0 10">

        <ComboBox 
            ItemsSource="{Binding Customers}"
            ItemTemplate="{StaticResource CustomerComboBoxTemplate}"
            Margin="20"
            HorizontalAlignment="Left"
            SelectedItem="{Binding SelectedCustomer, Mode=TwoWay}"/>

        <ListBox 
            ItemsSource="{Binding Customers}"
            ItemTemplate="{StaticResource CustomerRadioButtonTemplate}" 
            SelectedItem="{Binding SelectedCustomer, Mode=TwoWay}"/>


        <TextBlock Text="{Binding Customers.Count}"/>


        <Button Content="Add Customer" Command="{Binding AddCustomerCommand}"/>


    </StackPanel>

</DockPanel>

ViewModel:

using System;
using System.Collections.ObjectModel;
using TestSelectedItem234.Models;

namespace TestSelectedItem234.ViewModels
{
    public class MainViewModel : ViewModelBase
    {

        #region ViewModelProperty: Customers
        private ObservableCollection<Customer> _customers = new ObservableCollection<Customer>();
        public ObservableCollection<Customer> Customers
        {
            get
            {
                return _customers;
            }

            set
            {
                _customers = value;
                OnPropertyChanged("Customers");
            }
        }
        #endregion

        #region ViewModelProperty: SelectedCustomer
        private Customer _selectedCustomer;
        public Customer SelectedCustomer
        {
            get
            {
                return _selectedCustomer;
            }

            set
            {
                _selectedCustomer = value;
                OnPropertyChanged("SelectedCustomer");
            }
        }
        #endregion

        #region ViewModelProperty: CustomerIsSelected
        private bool _customerIsSelected;
        public bool CustomerIsSelected
        {
            get
            {
                return _customerIsSelected;
            }

            set
            {
                _customerIsSelected = value;
                OnPropertyChanged("CustomerIsSelected");
            }
        }
        #endregion

        public MainViewModel()
        {
            LoadCustomers();

            CustomerIsSelected = false;
        }

        private void LoadCustomers()
        {
            _customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", HireDate = DateTime.Parse("2007-12-31") });
            _customers.Add(new Customer { FirstName = "Jack", LastName = "Taylor", HireDate = DateTime.Parse("2005-12-31") });
            _customers.Add(new Customer { FirstName = "Jane", LastName = "Smith", HireDate = DateTime.Parse("2005-06-30") });
            _customers.Add(new Customer { FirstName = "Alice", LastName = "Jones", HireDate = DateTime.Parse("2005-08-23") });
            _customers.Add(new Customer { FirstName = "Mary", LastName = "Ashton", HireDate = DateTime.Parse("2005-12-22") });
            _customers.Add(new Customer { FirstName = "Joe", LastName = "Jones", HireDate = DateTime.Parse("2005-11-22") });
            _customers.Add(new Customer { FirstName = "Henry", LastName = "Smith", HireDate = DateTime.Parse("2005-12-11") });
            _customers.Add(new Customer { FirstName = "Allison", LastName = "Rodrigez", HireDate = DateTime.Parse("2004-12-14") });
            _customers.Add(new Customer { FirstName = "Angela", LastName = "Thompson", HireDate = DateTime.Parse("2003-03-14") });
            _customers.Add(new Customer { FirstName = "Shawna", LastName = "Quaker", HireDate = DateTime.Parse("2005-12-14") });

            SelectedCustomer = _customers[0];
        }

    }
}

Update:

I also tried this from Thomas, but it still doesn't connect IsChecked with IsSelected:

<ListBox ItemsSource="{Binding Customers}">
    <ListBox.ItemContainerStyle>
        <Style TargetType="{x:Type ListBoxItem}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ListBoxItem}">
                        <RadioButton Content="{Binding FirstName}" IsChecked="{Binding IsSelected, RelativeSource={x:Static RelativeSource.TemplatedParent}}"/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </ListBox.ItemContainerStyle>
</ListBox>

Answer 1

ItemsControl doesn't have a SelectedItem property, you should use a ListBox instead

This sample works fine :

<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:sys="clr-namespace:System;assembly=mscorlib">
  <Page.Resources>
    <x:Array x:Key="stringList" Type="sys:String">
      <sys:String>Hello</sys:String>
      <sys:String>World</sys:String>
      <sys:String>!</sys:String>
    </x:Array>
  </Page.Resources>
  <Grid>
    <ListBox ItemsSource="{StaticResource stringList}">
      <ListBox.ItemContainerStyle>
        <Style TargetType="{x:Type ListBoxItem}">
          <Setter Property="Template">
            <Setter.Value>
              <ControlTemplate TargetType="{x:Type ListBoxItem}">
                <RadioButton Content="{Binding}" IsChecked="{Binding IsSelected, RelativeSource={x:Static RelativeSource.TemplatedParent}}"/>
              </ControlTemplate>
            </Setter.Value>
          </Setter>
        </Style>
      </ListBox.ItemContainerStyle>
    </ListBox>
  </Grid>
</P