数据模板的绑定模型和视图模型

Question

I am relatively new to WPF and I try to show some data in a ListView .

I have a Model class Order which I want to simply show on the ListView . But I want to also show some other calculated informations (such as amount of Positions inside the order).

How do I achieve to use the OrderViewModel (ViewModel) and not the Order (Model) class for the DataTemplate of the ListView ?

Please tell me if you need more informations.

Thank you in advance!

Order class

This is my order class. It contains some information, but not everything I want to show on the ListView.

public class Order
{
    private int number;
    private ObservableCollection<Position> positions;


    /// <summary>
    /// Default Constructor
    /// </summary>
    public Order()
    {
        this.positions = new ObservableCollection<Position>();
    }

    /// <summary>
    /// Order Number
    /// </summary>
    public int Number
    {
        get { return number; }
        set { number = value; }
    }

    /// <summary>
    /// Positions inside the order.
    /// </summary>
    public ObservableCollection<Position> Positions
    {
        get { return positions; }
        set { positions = value; }
    }
}

Order ViewModel

This class is the ViewModel I want to show on the ListView.

public class OrderViewModel : ViewModelBase
{
    readonly private Order order;

    #region Constructor

    public OrderViewModel(Order order)
    {
        this.order = order;
    }

    #endregion Constructor

    #region Order Properties

    public string Number
    {
        get { return order.Number.ToString(); }
    }

    public ObservableCollection<Position> Positions
    {
        get
        {
            return order.Positions;
        }
    }

    #endregion Order Properties

    #region Presentation Properties

    public int AmountOfPositions // Calculated value should be shown on the ListView.
    {
        get { return order.Positions.Count; }
    }

    #endregion Presentation Properties
}

XAML of the ListView

  <ListView x:Name="orderListView" ItemsSource="{Binding Path=AvailableOrders}" Margin="0,54,0,0" SelectionMode="Single" 
              SelectedItem="{Binding Path=SelectedOrder}" >
        <ListView.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <TextBlock Text="{Binding Number}" />
                    <TextBlock Text="{Binding AmountOfPositions}" // This does not work! />
                </StackPanel>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

Answer 1

1. You need to set the DataContext of your XAML to the viewmodel.
2. You need to raise the property changed event that is ultimately exposed via your ViewModelBase