Inheritance of Attached Behaviors

I'd like to implement a set of similar attached behaviors for use in a WPF application. Since their all share a chunk of boilerplate code, that I don't really want to repeat for every one, I'd like to create a base behavior inherit from it. But since everything inside attached behaviors is static, I am at a loss of how to do it.

As an example, take this behavior, which executes a method on mousedown (the real behaviors would of course do something not easily done in an eventhandler):

public static class StupidBehavior
{
    public static bool GetIsEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsEnabledProperty);
    }

    public static void SetIsEnabled(DependencyObject obj, bool value)
    {
        obj.SetValue(IsEnabledProperty, value);
    }

    // Using a DependencyProperty as the backing store for ChangeTooltip.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty IsEnabledProperty =
        DependencyProperty.RegisterAttached("IsEnabled", typeof(bool)开发者_JAVA技巧, typeof(StupidBehavior), new UIPropertyMetadata(false, IsEnabledChanged));


    private static void IsEnabledChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
    {
        ((UIElement)sender).MouseDown += { (o,e) => MyMethod(); };
    }

    private static void MyMethod()
    {
        MessageBox.Show("Boo");
    }     
}

Now, I'd like to create a new behavior that should have a different implementation of MyMethod, as well as a few additional properties controlling it. How should this be done?

---

You could create another attached property which contains the detailed implementation which is being called by the main behavior as a sub-class replacement. The object that property holds could be non-static and be used like a state-object.

(You could probably fit this into one property as well, where property == null means off)

---

You could use a static constructor to form a Dictionary<DependencyProperty,EventHandler> to map the specific DP to a specific handler and use a common DependencyPropertyChanged callback:

static StupidBehavior()
{
    handlerDictionary[IsEnabledProperty] = (o,e) => MyMethod();
    handlerDictionary[SomeOtherProperty] = (o,e) => SomeOtherMethod();
}

private static void CommonPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
{
    var uie = sender as UIElement;
    if (uie != null)
    {
        //removing before possibly adding makes sure the multicast delegate only has 1 instance of this delegate
        sender.MouseDown -= handlerDictionary[args.Property];
        if (args.NewValue != null)
        {
            sender.MouseDown += handlerDictionary[args.Property];
        }
    }
}

Or simply do a switch on args.Property. Or something in-between that involves a common method and branching based on the DependencyProperty.

And I'm not sure why your IsEnabled property deals with a value of type DependencyProperty rather than something that would make more semantic sense like bool.