PropertyChangedCallback Delegasikan

Definisi

Ruang nama:

System.Windows

Rakitan:

WindowsBase.dll

Mewakili panggilan balik yang dipanggil ketika nilai properti efektif dari properti dependensi berubah.

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)

Parameter

d

DependencyObject

Tempat DependencyObject properti telah mengubah nilai.

e

DependencyPropertyChangedEventArgs

Data peristiwa yang dikeluarkan oleh peristiwa apa pun yang melacak perubahan pada nilai efektif properti ini.

Contoh

Contoh berikut mendaftarkan properti dependensi baru, menggunakan tanda tangan yang menentukan PropertyChangedCallback. PropertyChangedCallback digunakan untuk membuat panggilan balik yang mengubah properti internal setiap kali properti publik berubah.

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