PropertyChangedCallback 委托

定义

表示在依赖属性的有效属性值更改时调用的回调。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)

参数

d
DependencyObject

属性值已更改的 DependencyObjectThe DependencyObject on which the property has changed value.

e
DependencyPropertyChangedEventArgs

跟踪对此属性有效值的更改的任何事件发出的事件数据。Event data that is issued by any event that tracks changes to the effective value of this property.

继承
PropertyChangedCallback

示例

下面的示例使用指定的PropertyChangedCallback签名来注册新的依赖项属性。The following example registers a new dependency property, using the signature that specifies a PropertyChangedCallback. PropertyChangedCallback用于创建一个在公共属性更改时更改内部属性的回调。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

扩展方法

GetMethodInfo(Delegate)

获取指示指定委托表示的方法的对象。Gets an object that represents the method represented by the specified delegate.

适用于