c# - 如何将“SelectedItem”添加到自定义控件中？

Question

我ItemsRepeater用来展示一组物品。我想补充SelectedItem，但不明白怎么做。我的axaml：

<ScrollViewer>                                                                                                                           
    <ItemsRepeater Items="{Binding CollectionOfValues}" >                                                                                
        <ItemsRepeater.ItemTemplate>                                                                                                     
            <DataTemplate>                                                                                                               
                <Border Padding="{Binding Level, Converter={StaticResource PaddingConverter}}">                                          
                        <StackPanel Orientation="Horizontal">                                                                            
                            <CheckBox IsChecked="{Binding IsExpanded}"/>                                                                 
                            <TextBlock Focusable="True" Text="{Binding  Part}" Margin="3 0 0 0"/>                                        
                        </StackPanel>                                                                                                    
                    </Border>                                                                                                            
            </DataTemplate>                                                                                                              
        </ItemsRepeater.ItemTemplate>                                                                                                    
    </ItemsRepeater>                                                                                                                     
</ScrollViewer>

                   

缺少 SelectedItem 限制了我，我不能写这样的东西：

<vm:ReceivedApplicationMessageDetailsView                             
    DataContext="{Binding CollectionOfValues.SelectedItem.Details}" />