Binding selectedItem ListBox of Radio buttons in combobox popup - wpf

Question

Ok, so my question is kind of convoluted, so I'll try to be as clear as possible. Because a collection of radio buttons does not have a 'SelectedItem/Value' property, I have collected my radioButtons into a ListBox, based on some XAML I found online. Now, in order to save space on the UI, that ListBox is taking over the content of a ComboBox popup. (So when you click the comboBox, what drops down is a list of radiobuttons in a WrapPanel.) I have been able to successfully bind the RadioButton listbox control by itself to an itemssource and bind selected value to a property, but once inside the combo box, I cannot seem to get the selected value binding to work properly, (ItemsSource still works fine).
<Style x:Key="RadioButtonList" TargetType="{x:Type ListBox}">
<Setter Property="Background" Value="White"/>
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<WrapPanel Background="Transparent" />
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
<Setter Property="ItemContainerStyle">
<Setter.Value>
<Style TargetType="{x:Type ListBoxItem}" >
<Setter Property="Margin" Value="5" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<Border BorderThickness="1" Background="Transparent">
<RadioButton Focusable="False" Width="120"
IsHitTestVisible="False"
Content="{Binding Name}"
IsChecked="{TemplateBinding IsSelected}">
</RadioButton>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBox}">
<Border BorderThickness="0" Padding="0" BorderBrush="Transparent" Background="Transparent" Name="Bd" SnapsToDevicePixels="True">
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="RadioButtonCombo" TargetType="ComboBox">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ComboBox">
<Grid>
<ToggleButton
Name="ToggleButton"
DataContext="{TemplateBinding ItemsSource}"
Content="{Binding ElementName=DropDownContent, Path=SelectedItem.Name}"
Focusable="false"
IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}"
ClickMode="Press" />
<ContentPresenter
Name="ContentSite"
IsHitTestVisible="False"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
Margin="3,3,23,3"
VerticalAlignment="Center"
HorizontalAlignment="Left" />
<Popup Name="Popup" Placement="Bottom" IsOpen="{TemplateBinding IsDropDownOpen}"
AllowsTransparency="True" Focusable="False" PopupAnimation="Slide">
<Grid Name="DropDown" SnapsToDevicePixels="True"
MinWidth="{TemplateBinding ActualWidth}" MaxHeight="{TemplateBinding MaxDropDownHeight}">
<Border x:Name="DropDownBorder" Background="WhiteSmoke"
BorderThickness="1" BorderBrush="Black"/>
<ListBox Name="DropDownContent" Style="{StaticResource RadioButtonList}"
Width="{TemplateBinding MaxWidth}"
SelectedValue="{Binding Path=SelectedValue, RelativeSource={RelativeSource TemplatedParent}}"
ItemsSource="{TemplateBinding ItemsSource}">
</ListBox>
</Grid>
</Popup>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
</Style.Triggers>
</Style>
My use of that looks like this:
<ComboBox Name="SourceComboCtl"
Text="Source"
SelectedValuePath="CodeId"
DisplayMemberPath="Name"
SelectedValue="{Binding Path=SourceCode}"
Style="{StaticResource RadioButtonCombo}"
Width="60"
MaxWidth="150" />

Answer 1

I'm a bit confused why you'd first overwrite a ListBox to display RadioButtons, then overwrite a ComboBox to use a ListBox to display RadioButtons
Why not just overwrite ComboBox.ItemTemplate and skip the ListBox alltogether? ComboBox has SelectedItem/Value too
Here's my RadioButtonListBox Style. I simply changed where it says ListBox to say ComboBox
<Style x:Key="RadioButtonComboBoxStyle" TargetType="{x:Type ComboBox}">
<Setter Property="BorderBrush" Value="Transparent"/>
<Setter Property="KeyboardNavigation.DirectionalNavigation" Value="Cycle" />
<Setter Property="ItemContainerStyle">
<Setter.Value>
<Style TargetType="{x:Type ComboBoxItem}" >
<Setter Property="Margin" Value="2, 2, 2, 0" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border Background="Transparent">
<RadioButton IsHitTestVisible="False" Focusable="false"
Content="{TemplateBinding ContentPresenter.Content}"
IsChecked="{Binding Path=IsSelected,RelativeSource={RelativeSource TemplatedParent},Mode=TwoWay}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>