c# - WPF——自定义控件——继承DependencyProperty和PropertyChangedCallback

Question

对于像下面这样的Custom Control，如何为继承的DependencyProperty IsEnabledProperty添加PropertyChangedCallback？

public class MyCustomControl : ContentControl
{
      // Custom Dependency Properties

      static MyCustomControl ()
      {
           DefaultStyleKeyProperty.OverrideMetadata(typeof(MyCustomControl), new FrameworkPropertyMetadata(typeof(MyCustomControl)));
           // TODO (?) IsEnabledProperty.OverrideMetadata(typeof(MyCustomControl), new PropertyMetadata(true, CustomEnabledHandler));
      }

      public CustomEnabledHandler(DependencyObject d, DependencyPropertyChangedEventArgs e)
      {
           // Implementation
      }
}

---

是的，还有另一个选项，比如监听 IsEnabledChangeEvent

public class MyCustomControl : ContentControl
{
      public MyCustomControl()
      {
           IsEnabledChanged += …
      }
}

但我不喜欢在每个实例中都注册事件处理程序的方法。所以我更喜欢元数据覆盖。

Answer 1

这个有效:

static MyCustomControl()
{
    DefaultStyleKeyProperty.OverrideMetadata(typeof(MyCustomControl),
        new FrameworkPropertyMetadata(typeof(MyCustomControl)));

    IsEnabledProperty.OverrideMetadata(typeof(MyCustomControl),
        new FrameworkPropertyMetadata(IsEnabledPropertyChanged));
}

private static void IsEnabledPropertyChanged(
    DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
    Debug.WriteLine("{0}.IsEnabled = {1}", obj, e.NewValue);
}