.NET Design Patterns

Observer pattern in the WPF

The ObservableCollection can be considered as a data structure, which leverages the observer pattern to provide notifications when items get added or removed, or when the whole list is refreshed:

    class ObservableDataSource  
    { 
      public ObservableCollection<string> data  
      { get; set; } 
 
      public ObservableDataSource() 
      { 
        data = new ObservableCollection<string>(); 
        data.CollectionChanged += OnCollectionChanged; 
      } 
      void OnCollectionChanged(object sender,  
      NotifyCollectionChangedEventArgs args)  
      { 
        Console.WriteLine("The Data got changed ->" +  
        args.NewItems[0]); 
      } 
      public void TearDown() 
      { 
        data.CollectionChanged -= OnCollectionChanged; 
      } 
    } 

The following code snippet creates an instance of an Observableconnection based ObservableDataSource ...