PropertyChangedCallback 委托

定义

命名空间:
System.Windows
程序集:
WindowsBase.dll

表示在依赖属性的有效属性值发生更改时调用的回调。

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 DependencyObject 已更改值的依据。

e
DependencyPropertyChangedEventArgs

跟踪对此属性的有效值的更改的任何事件发出的事件数据。

示例

以下示例使用指定 a PropertyChangedCallback. 用于 PropertyChangedCallback 创建回调，每当公共属性发生更改时，该回调将更改内部属性。

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

名称 说明
GetMethodInfo(Delegate)

获取一个对象，该对象表示由指定委托表示的方法。

适用于