WPF Binding nested path demo

// View model as per OP's example
public class ViewModel : INotifyPropertyChanged
{
    Car _myCarProperty;

    public Car MyCarProperty
    {
        get { return _myCarProperty; }
        set
        {
            if (value == _myCarProperty) return;

            _myCarProperty = value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

// Further viewmodels to demonstrate nested property path binding
public class Car
{
    public Car(string make)
    {
        Make = make;
        Model = new Model(make);
    }

    public string Make { get; set; }

    public Model Model { get; }
}

public class Model
{
    public Model(string make)
    {
        Name = make + "tron";
        SuperNested = new SuperNested(Name);
    }

    public string Name { get; }

    public SuperNested SuperNested { get; }
}

public class SuperNested
{
    readonly int _nestLevel;
    readonly string _name;

    public SuperNested(string name, int nestLevel = 0)
    {
        _name = name;
        _nestLevel = nestLevel;
    }

    public SuperNested this[string any] => new SuperNested(_name, _nestLevel + 1);

    public string Name => _name + " L" + _nestLevel;
}


// MainWindow.xaml.cs
public partial class MainWindow
{
    readonly ViewModel _viewModel;

    public MainWindow()
    {
        _viewModel = new ViewModel {MyCarProperty = new Car("Audi")};

        DataContext = _viewModel;

        InitializeComponent();
    }

    void OnChangeMyCarPropertyClicked(object sender, RoutedEventArgs e)
    {
        // The view will be notified of this property change, no matter how deep the "Path" is.
        _viewModel.MyCarProperty = new Car(_textBox.Text);
    }

    void OnChangeMakeDirectlyClicked(object sender, RoutedEventArgs e)
    {
        //This is the part WPF will not pick up automatically, UNLESS you add NotifyPropertyChanged for the "Make" property.
        _viewModel.MyCarProperty.Make = _textBox.Text;
    }
}

// MainWindow.xaml
<Window
    x:Class="NestedBindingSOExample.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Title="MainWindow"
    Height="350"
    Width="525">
    <Grid>
        <StackPanel
            VerticalAlignment="Center">
            <StackPanel
                Orientation="Horizontal"
                HorizontalAlignment="Center">
                <TextBlock
                    Text="MyCarProperty.Make Xaml Bound:"
                    Margin="0,0,10,0" />
                <TextBlock
                    Text="{Binding Path=MyCarProperty.Make}" />
            </StackPanel>
            <StackPanel
                Orientation="Horizontal"
                HorizontalAlignment="Center">
                <TextBlock
                    Text="MyCarProperty.Model.SuperNested Xaml Bound:"
                    Margin="0,0,10,0" />
                <TextBlock
                    Text="{Binding Path=MyCarProperty.Model.SuperNested[any][thing][you][want][to][try][and][access].Name}" />
            </StackPanel>
            <Label
                Margin="0,15,0,0"
                HorizontalAlignment="Center"
                Content="Enter New Make:" />
            <TextBox
                Margin="0,3,0,0"
                HorizontalAlignment="Center"
                Width="150"
                x:Name="_textBox" />
            <Button
                Margin="0,7,0,0"
                HorizontalAlignment="Center"
                Width="150"
                Content="Change MyCarProperty"
                Click="OnChangeMyCarPropertyClicked" />
            <Button
                Margin="0,7,0,0"
                HorizontalAlignment="Center"
                Width="150"
                Content="Change Make Name"
                Click="OnChangeMakeDirectlyClicked"
                ToolTip="This wont work out of the box, unless you add NotifyPropertyChanged" />
        </StackPanel>
    </Grid>
</Window>