What does Binding Path=Name mean in WPF?

Question

I am newbie and am confused of some syntax of ListBox.GroupStyle. The code:

    <Window x:Class="testCollectionViewSource.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            Title="MainWindow" Height="350" Width="525">
        <Window.Resources>
            <CollectionViewSource x:Key="CVS" Source="{Binding Path=Cs}">
                <CollectionViewSource.GroupDescriptions>
                    <PropertyGroupDescription PropertyName="B" />
                </CollectionViewSource.GroupDescriptions>
            </CollectionViewSource>
        </Window.Resources>
        <Grid>
            <ListBox ItemsSource="{Binding Source={StaticResource CVS}}">

                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <TextBlock   Text="{Binding S}"/>
                    </DataTemplate>
                </ListBox.ItemTemplate>

                <ListBox.GroupStyle>
                    <GroupStyle>
                        <GroupStyle.HeaderTemplate>
                            <DataTemplate>
                                <TextBlock Text="{Binding Name}"/>
                            </DataTemplate>
                        </GroupStyle.HeaderTemplate>
                    </GroupStyle>
                </ListBox.GroupStyle>

            </ListBox>

        </Grid>
    </Window>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        Cs = new ObservableCollection<C>();
        Cs.Add(new C(true, "1"));
        Cs.Add(new C(false, "2"));
        Cs.Add(new C(true, "3"));
        Cs.Add(new C(false, "4"));
        DataContext = this;
    }

    public ObservableCollection<C> Cs { get; set; }
}

public class C
{
    public C(bool b, string s)
    {
        B = b;
        S = s;
    }
    public bool B { get; set; }
    public string S { get; set; }
}

So my question is why only when {Binding Name} does the header displays "True" or "False", and why {Binding B} not work? What does "Name" mean, since the Class C does not have such property.

Answer 1

If you inspect the application using Snoop, you'll realize the DataContext of your TextBlock and it's ancestors up to the GroupItem is an object of type MS.Internal.Data.CollectionViewGroupInternal, which contains a Name property:

This is why {Binding Name} works in there, while {Binding B} does not.