DC Superhero ListView and TextBoxes

HeroDetailControl.xaml

<UserControl
    x:Class="Superheroes.HeroDetailControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:Superheroes"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300"
    d:DesignWidth="400"
    >

    <StackPanel>

        <TextBox 
            x:Name="FirstNameTextbox"
            Header="First name" 
            Margin="10"
            Text="{x:Bind Hero.FirstName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
            GotFocus="Textbox_GotFocus"
            />
        <TextBox 
            x:Name="LastNameTextbox"
            Header="Last name" 
            Margin="10"
            Text="{x:Bind Hero.LastName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
            GotFocus="Textbox_GotFocus"
            />
        <TextBox 
            x:Name="SuperheroTextbox"
            Header="Alias" 
            Margin="10"
            Text="{x:Bind Hero.Superhero,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
            GotFocus="Textbox_GotFocus"
            />
    </StackPanel>
</UserControl>

HeroDetailControl.xaml.cs

using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace Superheroes
{
    public sealed partial class HeroDetailControl : UserControl
    {
        public Hero Hero
        {
            get { return (Hero)GetValue(HeroProperty); }
            set { SetValue(HeroProperty, value); }
        }

        public static readonly DependencyProperty HeroProperty =
            DependencyProperty.Register("Hero", typeof(Hero), typeof(HeroDetailControl), new PropertyMetadata(null, HeroChangedCallback));

        private static void HeroChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
        }

        public HeroDetailControl()
        {
            this.InitializeComponent();
        }

        private void Textbox_GotFocus(object sender, RoutedEventArgs e)
        {
            TextBox txtbox = sender as TextBox;
            txtbox.SelectAll();
        }
    }
}

MainPage.xaml

<Page
    x:Class="Superheroes.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:Superheroes"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <StackPanel>
        <CommandBar>
            <AppBarButton x:Name="AddHero" Click="AddHero_Click" Label="Add hero">
                <SymbolIcon Symbol="Add"/>
            </AppBarButton>
            <AppBarButton x:Name="DelHero" Click="DelHero_Click" Label="Remove hero" IsEnabled="{x:Bind ViewModel.IsHeroSelected,Mode=OneWay}">
                <SymbolIcon Symbol="Delete"/>
            </AppBarButton>
        </CommandBar>

        <local:HeroDetailControl Hero="{Binding ElementName=heroesListView,Path=SelectedItem,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
        <ListView 
            x:Name="heroesListView" 
            ItemsSource="{x:Bind ViewModel.Heroes,Mode=OneWay}" 
            SelectedItem="{x:Bind ViewModel.SelectedHero,Mode=TwoWay}"
            Margin="0"
            >
            <ListView.ItemTemplate>
                <DataTemplate x:DataType="local:Hero">
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{x:Bind Superhero,Mode=OneWay}" FontWeight="Bold"/>
                        <TextBlock Text="{x:Bind FirstName,Mode=OneWay}" Margin="5 0 0 0"/>
                        <TextBlock Text="{x:Bind LastName,Mode=OneWay}" Margin="5 0 0 0"/>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

    </StackPanel>
</Page>

MainPage.xaml.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Windows.UI.Xaml.Controls;


namespace Superheroes
{

    public class Observable : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class Hero : Observable
    {
        private string superhero;
        private string lastName;
        private string firstName;

        public string FirstName
        {
            get => firstName; set
            {
                firstName = value;
                OnPropertyChanged();
            }
        }
        public string LastName
        {
            get => lastName; set
            {
                lastName = value;
                OnPropertyChanged();
            }
        }
        public string Superhero
        {
            get => superhero; set
            {
                superhero = value;
                OnPropertyChanged();
            }
        }
        public Hero(string fn, string ln, string s)
        {
            FirstName = fn;
            LastName = ln;
            Superhero = s;
        }
        public Hero() : this("John", "Doe", "Captain Underpants") { }

    }


    public class ViewModel : Observable
    {
        public bool IsHeroSelected => SelectedHero != null;

        public ObservableCollection<Hero> Heroes { get; }

        private Hero _selectedHero;

        public Hero SelectedHero
        {
            get { return _selectedHero; }
            set
            {
                _selectedHero = value;
                OnPropertyChanged();
                OnPropertyChanged(nameof(IsHeroSelected));
            }
        }


        public ViewModel()
        {
            Heroes = new ObservableCollection<Hero>();
            Heroes.Add(new Hero("Clark","Kent","Superman"));
            Heroes.Add(new Hero("Bruce", "Wayne", "Batman"));
            Heroes.Add(new Hero("Hal", "Jordan", "Green Lantern"));
            Heroes.Add(new Hero("Diana", "Prince", "Wonder Woman"));
        }


    }
    public sealed partial class MainPage : Page
    {
        public ViewModel ViewModel { get; }

        public MainPage()
        {
            this.InitializeComponent();
            this.ViewModel = new ViewModel();
            DataContext = ViewModel;
        }

        private void AddHero_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        {
            var hero = new Hero();
            ViewModel.Heroes.Add(hero);
            ViewModel.SelectedHero = hero;
        }

        private void DelHero_Click(object sender, Windows.UI.Xaml.RoutedEventArgs e)
        {
            ViewModel.Heroes.Remove(ViewModel.SelectedHero);
        }
    }
}