PropertyChangedCallback Delegate (System.Windows)

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PropertyChangedCallback Delegate

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

PropertyChangedCallback Delegate

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

Namespace: System.Windows
Assembly: WindowsBase (in WindowsBase.dll)

Syntax

Visual Basic (Declaration)

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

Visual Basic (Usage)

Dim instance As New PropertyChangedCallback(AddressOf HandlerMethod)

public delegate void PropertyChangedCallback(
    DependencyObject d,
    DependencyPropertyChangedEventArgs e
)

Visual C++

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

JScript

JScript does not support delegates.

XAML

In XAML, you can use delegates but you cannot define your own.

Parameters

d: Type: System.Windows..::.DependencyObject
The DependencyObject on which the property has changed value.

e: Type: System.Windows..::.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)
  )
);

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

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0

Reference

System.Windows Namespace

Other Resources

Custom Dependency Properties

Dependency Property Callbacks and Validation

PropertyChanged and CoerceValue Callbacks Sample