How to launch the simplest code illustrating Master-Detail (compound List) object databinding in WPF?

Question

I am trying to run (in C# 4.0, Visual Studio 2010) the code from

• Unable to display a List as one of the columns of my view with ItemsControl and StackPanel?

Answer 1

The simpler answer:
This is funny but I do not see in HichemC's answer edits his penultimate edition of C# code working with the same XAML without any bloating by:

• ObservableCollection
• OnPropertyChanged()
• INotifyPropertyChanged
• PropertyChangedEventHandler

That this, simpler, code works for me:

public partial class MainWindow : Window
{
    public List<Order> myOrders { get; set; }
    Order order1 = new Order
    {
        OrderName = "Order1",
        PartsList = new List<Parts>()
        {
              new Parts {PartName = "Part11", PartQuantity = 11},
              new Parts {PartName = "Part12", PartQuantity = 12}
         }
     };
    Order order2 = new Order
    {
        OrderName = "Order2",
        PartsList = new List<Parts>()
        {
              new Parts {PartName = "Part21", PartQuantity = 21},
              new Parts {PartName = "Part22", PartQuantity = 22},
              new Parts {PartName = "Part23", PartQuantity = 23}
         }
     };

     public MainWindow()
        {
            InitializeComponent();
            myOrders = new List<Order>();
            myOrders.Add(order1);
            myOrders.Add(order2);
            DataContext = this;
        }
    }
    public class Order
    {
        public string OrderName { get; set; }
        public List<Parts> PartsList { get; set; }
    }

    public class Parts
    {
        public string PartName { get; set; }
        public double PartQuantity { get; set; }
        }
}

Answer 2

First of all myOrders has to be a public property. it cannot be seen even if it's a public variable, secondly to make the view(XAML) aware of what's going in the code behind you need to set DataContext = this; in the window's constructor

Set a property like this : public List<Order> myOrder {get;set;}

If you need to update the view from code behind then you need to implement INotifyPropertyChanged interface. it's responsible of doing update view job. Here is a small tutorial from MSDN.

Last thing, (From my experience) you should go with a property of type ObservableCollection<Order> instead of List<Order>.

XAML :

<Grid>
  <ItemsControl  x:Name="visual"
                 ItemsSource="{Binding MyOrders}"
                 HorizontalAlignment="Stretch"
                 HorizontalContentAlignment="Stretch">
    <ItemsControl.ItemTemplate>
      <!-- This defines the DataTemplate to display one Order object-->
      <DataTemplate>
        <StackPanel>
          <TextBlock Text="{Binding OrderName}"
                     Margin="10" />

          <ItemsControl ItemsSource="{Binding PartsList}"
                        HorizontalAlignment="Stretch"
                        HorizontalContentAlignment="Stretch">
            <ItemsControl.ItemTemplate>
              <!-- This defines the DataTemplate to display one Parts object-->
              <DataTemplate>
                <Grid HorizontalAlignment="Stretch">
                  <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="*" />
                  </Grid.ColumnDefinitions>
                  <TextBlock Grid.Column="0"
                             Text="{Binding PartName}"
                             TextAlignment="Center" />
                  <TextBlock Grid.Column="1"
                             Text="{Binding PartQuantity}"
                             TextAlignment="Center" />
                </Grid>
              </DataTemplate>
            </ItemsControl.ItemTemplate>
          </ItemsControl>
        </StackPanel>
      </DataTemplate>
    </ItemsControl.ItemTemplate>
  </ItemsControl>
</Grid>

Code behind :

  /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window, INotifyPropertyChanged
{
    public ObservableCollection<Order> MyOrders
    {
        get { return _myOrders; }
        set { _myOrders = value; OnPropertyChanged("MyOrders"); }
    }

    Order order1 = new Order
     {
         OrderName = "Order1",
         PartsList = new List<Parts>()
        {
            new Parts {PartName = "Part11", PartQuantity = 11},
            new Parts {PartName = "Part12", PartQuantity = 12}
        }
     };

    private ObservableCollection<Order> _myOrders;

    public MainWindow()
    {
        InitializeComponent();
        MyOrders = new ObservableCollection<Order>();
        MyOrders.Add(order1);
        DataContext = this;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
}
    public class Order
    {
        public string OrderName { get; set; }
        public List<Parts> PartsList { get; set; }
    }

    public class Parts
    {
        public string PartName { get; set; }
        public double PartQuantity { get; set; }
        }
}