c# - 获取依赖属性内的 'this' 指针更改回调

Question

我在一个类中有以下依赖属性:

class FooHolder
{
    public static DependencyProperty CurrentFooProperty = DependencyProperty.Register(
        "CurrentFoo",
        typeof(Foo), 
        typeof(FooHandler),
        new PropertyMetadata(OnCurrentFooChanged));

    private static void OnCurrentFooChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        FooHolder holder = (FooHolder) d.Property.Owner; // <- something like this

        // do stuff with holder
    }
}

我需要能够检索对更改的属性所属的类实例的引用。

这是因为 FooHolder 有一些事件处理程序需要在属性值更改时挂接/取消挂接。属性更改回调必须是静态的，但事件处理程序不是。

Answer 1

像这样:(你必须自己定义 UnwireFoo() 和 WireFoo())

private static void OnCurrentFooChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    FooHolder holder = (FooHolder)d; // <- something like this

    holder.UnwireFoo(e.OldValue as Foo);
    holder.WireFoo(e.NewValue as Foo);
}

当然，FooHolder 必须继承自 DependencyObject