c# - 私有(private) WPF 依赖属性

Question

在我的 WPF 项目中，我需要为多个具有相同值的属性设置动画。所以我的想法是创建一个自定义的、私有(private)的依赖属性来应用动画。不幸的是这似乎不起作用。 DependencyPropertyDescriptor.FromProperty() 始终为此属性返回 null。这是代码:

public partial class PedestrianVisual : UserControl {
  private static readonly DependencyProperty CurrentInaccuracyRadiusProperty =
    DependencyProperty.Register("CurrentInaccuracyRadius", typeof(double), typeof(PedestrianVisual));
  private double CurrentInaccuracyRadius {
    get { return (double)GetValue(CurrentInaccuracyRadiusProperty); }
    set { SetValue(CurrentInaccuracyRadiusProperty, value); }
  }

  public PedestrianVisual() {
    InitializeComponent();

    // This returns "null" all the time.
    DependencyPropertyDescriptor dpd = DependencyPropertyDescriptor.FromProperty(
      CurrentInaccuracyRadiusProperty, typeof(PedestrianVisual));
    dpd.AddValueChanged(this, (s, e) => { 
      UpdateInaccuracyCircle((double)GetValue(CurrentInaccuracyRadiusProperty)); 
    });
  }

  private void UpdateInaccuracyCircle(double curRadius) {
    // do something here
  }
}

还有其他方法来创建私有(private)依赖属性吗？

Answer 1

我不明白你为什么要这样做，我在声明中附加回调时没有遇到任何问题，例如像这样的东西:

private static readonly DependencyProperty CurrentInaccuracyRadiusProperty =
    DependencyProperty.Register
    (
        "CurrentInaccuracyRadius",
        typeof(double),
        typeof(PedestrianVisual),
        new UIPropertyMetadata(0.0, (s, e) =>
        {
            UpdateInaccuracyCircle((PedestrianVisual)s, (double)e.NewValue);
        })
    );

(在这种情况下UpdateInaccuracyCircle方法应该是静态的)

如果您想坚持使用实例方法:

private static readonly DependencyProperty CurrentInaccuracyRadiusProperty =
    DependencyProperty.Register
    (
        "CurrentInaccuracyRadius",
        typeof(double),
        typeof(PedestrianVisual),
        new UIPropertyMetadata(0.0, (s, e) =>
        {
            ((PedestrianVisual)s).UpdateInaccuracyCircle((double)e.NewValue);
        })
    );