若要在将客户端与数据源进行绑定时发出更改通知，则绑定类型应具有下列功能：实现INotifyPropertyChanged接口。
当绑定的属性改变时，它可以通知客户端，并进行界面数据更新。而我们不用写很多复杂的代码来更新界面数据，这样可以做到方法简洁而清晰，松耦合和让方法变得更通用。可用的地方太多了：例如上传进度，实时后台数据变更等地方。
（另：对于集合Model：INotifyCollectionChanged结接口会有ObservableCollection自动实现（见上一篇））
一个简单的例子：（下面的例子中TextBlock绑定了DataContext的ModelName，点击按钮以后model更新，TextBlock会自动更新）
Model：
1 public class MyModel : INotifyPropertyChanged
2 {
3 public event PropertyChangedEventHandler PropertyChanged;
4
5 public int ModelID { get; set; }
6
7 private string _ModelName;
8 public string ModelName
9 {
10 get { return _ModelName; }
11 set
12 {
13 _ModelName = value;
14
15 if (PropertyChanged != null)
16 {
17 PropertyChanged(this, new PropertyChangedEventArgs("ModelName"));
18 }
19 }
20 }
21 }
2 {
3 public event PropertyChangedEventHandler PropertyChanged;
4
5 public int ModelID { get; set; }
6
7 private string _ModelName;
8 public string ModelName
9 {
10 get { return _ModelName; }
11 set
12 {
13 _ModelName = value;
14
15 if (PropertyChanged != null)
16 {
17 PropertyChanged(this, new PropertyChangedEventArgs("ModelName"));
18 }
19 }
20 }
21 }
Silverlight页面：
1 <Grid x:Name="LayoutRoot" Background="White">
2 <TextBlock Height="46" HorizontalAlignment="Left" Margin="187,51,0,0" Name="textBlock1" Text="{Binding ModelName}" VerticalAlignment="Top" Width="94" />
3 <Button Content="update" Height="39" HorizontalAlignment="Left" Margin="187,120,0,0" Name="button1" VerticalAlignment="Top" Width="106" Click="button1_Click" />
4 </Grid>
2 <TextBlock Height="46" HorizontalAlignment="Left" Margin="187,51,0,0" Name="textBlock1" Text="{Binding ModelName}" VerticalAlignment="Top" Width="94" />
3 <Button Content="update" Height="39" HorizontalAlignment="Left" Margin="187,120,0,0" Name="button1" VerticalAlignment="Top" Width="106" Click="button1_Click" />
4 </Grid>
页面代码：
1 public MyView()
2 {
3 InitializeComponent();
4
5 MyModel m1 = new MyModel() { ModelID = 1, ModelName = "abc" };
6
7 this.DataContext = m1;
8 }
9
10 private void button1_Click(object sender, RoutedEventArgs e)
11 {
12 (this.DataContext as MyModel).ModelName = "abc_changed";
13 }
2 {
3 InitializeComponent();
4
5 MyModel m1 = new MyModel() { ModelID = 1, ModelName = "abc" };
6
7 this.DataContext = m1;
8 }
9
10 private void button1_Click(object sender, RoutedEventArgs e)
11 {
12 (this.DataContext as MyModel).ModelName = "abc_changed";
13 }
甚至还有一个VS2010插件来完成这个工作：NotifyPropertyWeaver
ViewModel也可以实现INotifyPropertyChanged接口，很简单：
XAML绑定集合：
1 <DataGrid ItemsSource="{Binding Path=LineItems}" />
ViewModel代码：
1 public class OrderViewModel : INotifyPropertyChanged
2 {
3 public OrderViewModel( IOrderService orderService )
4 {
5 this.LineItems = new ObservableCollection<OrderLineItem>(
6 orderService.GetLineItemList() );
7 }
8
9 public ObservableCollection<OrderLineItem> LineItems { get; private set; }
10 }
2 {
3 public OrderViewModel( IOrderService orderService )
4 {
5 this.LineItems = new ObservableCollection<OrderLineItem>(
6 orderService.GetLineItemList() );
7 }
8
9 public ObservableCollection<OrderLineItem> LineItems { get; private set; }
10 }