PropertyChangedCallback Delegate

Definition

Namespace:

System.Windows

Assembly:

WindowsBase.dll

Represents the callback that is invoked when the effective property value of a dependency property changes.

public delegate void PropertyChangedCallback(DependencyObject ^ d, DependencyPropertyChangedEventArgs e);

public delegate void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e);

type PropertyChangedCallback = delegate of DependencyObject * DependencyPropertyChangedEventArgs -> unit

Public Delegate Sub PropertyChangedCallback(d As DependencyObject, e As DependencyPropertyChangedEventArgs)

Parameters

d

DependencyObject

The DependencyObject on which the property has changed value.

e

DependencyPropertyChangedEventArgs

Event data that is issued by any event that tracks changes to the effective value of this property.

Examples

The following example registers a new dependency property, using the signature that specifies a PropertyChangedCallback. The PropertyChangedCallback is used to create a callback that changes an internal property whenever the public property changes.

public static readonly DependencyProperty AquariumGraphicProperty = DependencyProperty.Register(
  "AquariumGraphic",
  typeof(Uri),
  typeof(AquariumObject),
  new FrameworkPropertyMetadata(null,
      FrameworkPropertyMetadataOptions.AffectsRender, 
      new PropertyChangedCallback(OnUriChanged)
  )
);

Public Shared ReadOnly AquariumGraphicProperty As DependencyProperty = DependencyProperty.Register("AquariumGraphic", GetType(Uri), GetType(AquariumObject), New FrameworkPropertyMetadata(Nothing, FrameworkPropertyMetadataOptions.AffectsRender, New PropertyChangedCallback(AddressOf OnUriChanged)))

private static void OnUriChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
  Shape sh = (Shape) d;
  sh.Fill = new ImageBrush(new BitmapImage((Uri)e.NewValue));
}

Private Shared Sub OnUriChanged(ByVal d As DependencyObject, ByVal e As DependencyPropertyChangedEventArgs)
    Dim sh As Shape = CType(d, Shape)
    sh.Fill = New ImageBrush(New BitmapImage(CType(e.NewValue, Uri)))
End Sub

Extension Methods