using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;

namespace DataGridCollapsed
{
  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();
    }
    private void Expander_Expanded(object sender, RoutedEventArgs e)
    {
      for (var vis = sender as Visual; vis != null; vis = VisualTreeHelper.GetParent(vis) as Visual)
        if (vis is DataGridRow)
        {
          var row = (DataGridRow)vis;
          row.DetailsVisibility = row.DetailsVisibility == Visibility.Visible ? Visibility.Collapsed : Visibility.Visible;
          break;
        }
    }

    private void Expander_Collapsed(object sender, RoutedEventArgs e)
    {
      for (var vis = sender as Visual; vis != null; vis = VisualTreeHelper.GetParent(vis) as Visual)
        if (vis is DataGridRow)
        {
          var row = (DataGridRow)vis;
          row.DetailsVisibility = row.DetailsVisibility == Visibility.Visible ? Visibility.Collapsed : Visibility.Visible;
          break;
        }
    }
  
  }
  public class ViewModel : INotifyPropertyChanged
  {

    private CollectionViewSource cvs = new CollectionViewSource();
    private ObservableCollection<Person> persons = new ObservableCollection<Person>();
    public ObservableCollection<Person> Persons
    {
      get { return persons; }
      set { persons = value; OnPropertyChanged(); }

    }
    private Person selectedPerson = null;
    public Person SelectedPerson { get => this.selectedPerson; set { this.selectedPerson = value; OnPropertyChanged(); } }

    public ICollectionView View
    {
      get
      {
        if (cvs.Source == null)
        {
          GetData();
          cvs.View.CurrentChanged +=(s,e)=> SelectedPerson = cvs.View.CurrentItem as Person;

        }
        return cvs.View;
      }
    }
    private void GetData()
    {
      for (int i = 1; i < 6; i++)
      {
        Person p = new Person { ID = i, Name = $"Name {i}" };
        Persons.Add(p);
        for (int j = 0; j < 5; j++)
          p.Details.Add(new Detail() { Title = "title", Address = $"Address{j}" });
      }
      cvs.Source = Persons;
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propertyName = "") =>
      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
  }
  public class Person
  {
    public int ID { get; set; }
    public string Name { get; set; }
    public ObservableCollection<Detail> Details { get; set; } = new ObservableCollection<Detail>();
  }

  public class Detail
  {
    public string Title { get; set; }
    public string Address { get; set; }
  }
}