WPF ObservableCollection und INotifyCollectionChanged

Frank Dzaebel, erstellt am: 17.7.2008, zuletzt geändert: 17.7.2008
Kategorie: WPF, .NET-Version: 3.5, [Download]

Dieser Artikel zeigt eine Möglichkeit in WPF, wie eine ObservableCollection<T> über eine Änderung eines seiner Elemente nach aussen hin benachrichtigen kann.

Window1.cs:

using System.Windows;
using System.Collections.Specialized;
using System.Diagnostics;

namespace WpfListView
{
  /// <summary> Interaktionslogik für Window1.xaml </summary>
  public partial class Window1 : Window
  {
    public Window1()
    {
      InitializeComponent();
      Liste liste = (Liste)FindResource("liste");
      for (int i = 0; i < 100; i++)
        liste.Add(new Customer());
      liste.CollectionChanged += new NotifyCollectionChangedEventHandler(liste_CollectionChanged);
      liste[3].Nachname = "neu";
    }

    void liste_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
      Debugger.Break();
    } 
  }
}

Window1.xaml:

<Window x:Class="WpfListView.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300"
    xmlns:local="clr-namespace:WpfListView">
  
  <Window.Resources>
    <local:Liste x:Key="liste" x:Name="liste" />
  </Window.Resources>
  <ListView ItemsSource="{Binding Source={StaticResource ResourceKey=liste}}">
    <ListView.View>
      <GridView>
        <GridViewColumn Header="Vorname" DisplayMemberBinding="{Binding Path=Vorname}" />
        <GridViewColumn Header="Nachname" DisplayMemberBinding="{Binding Path=Nachname}" />
      </GridView>
    </ListView.View>
  </ListView>
</Window>  
Liste.cs:

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Collections.Specialized;

namespace WpfListView
{
  public class Liste : ObservableCollection<Customer>
  {
    protected override void InsertItem(int index, Customer item)
    {
      base.InsertItem(index, item);
      this[index].PropertyChanged += new PropertyChangedEventHandler(Liste_PropertyChanged);
    }

    void Liste_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
      OnCollectionChanged(new NotifyCollectionChangedEventArgs(
        NotifyCollectionChangedAction.Reset));
    }
  }

  public class Customer : INotifyPropertyChanged
  {
    #region INotifyPropertyChanged Member

    public event PropertyChangedEventHandler PropertyChanged;

    void NotifyPropertyChanged(string propertyName)
    {
      if (PropertyChanged != null)
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion

    #region Vorname
    string vorname = "Peter";

    public string Vorname
    {
      get { return vorname;}
      set
      {
        if (value != vorname)
        {
          vorname = value;
          NotifyPropertyChanged("Vorname");
        }
      }
    }
    #endregion

    #region Nachname
    string nachname = "Forstmeier";

    public string Nachname
    {
      get {return nachname;}
      set
      {
        if (value != nachname)
        {
          nachname = value;
          NotifyPropertyChanged("Nachname");
        }
      }
    }
    #endregion
  }
}