混合行为-您可以绑定到它们的属性吗? [英] Blend Behaviours - can you bind to their properties?

问题描述

我目前正在将我创建的许多附加行为迁移到Blend Behaviors，以便它们在Expression Blend中支持拖放.我注意到Blend行为的作者倾向于将行为属性定义为依赖项属性.

I am currently migrating a number of attached behaviours I have created to Blend Behaviours so that they support drag and drop within Expression Blend. I have noticed that authors of Blend behaviours tend to define the behaviour properties as dependency properties.

我创建了一个行为TiltBehaviour，该行为公开了类型为double的公共依赖项属性TiltFactor.在Expression Blend中，我可以设置此属性的值，但是，添加数据绑定..."的选项显示为灰色:

I have created a behaviour, TiltBehaviour, which exposes a public dependency property, TiltFactor, of type double. Within Expression Blend I can set the value of this property, however, the option to add a "Data Binding ..." is grayed out:

我还注意到，行为扩展了DependencyObject，因此它们没有DataContext，因此不能继承它们所附加的元素的DataContext.对我来说，这真是一个真正的弱点！

I have also noticed that Behaviors extend DependencyObject, therefore they do not have a DataContext and therefore cannot inherit the DataContext of the element to which they are attached. This feels like a real weakness to me!

因此，最重要的是，如果我无法在Blend中为我的行为依赖项属性设置绑定，并且它不继承DataContext，为什么还要使用依赖项属性呢?我可以改用CLR属性.

So, the bottom-line is, if I cannot set a binding to my behaviors dependency property in Blend, and it does not inherit a DataContext, why bother using dependency properties at all? I could just use CLR properties instead.

推荐答案

dain是正确的，您仍然可以绑定到人为创建的DataContext，您见过人们多久绑定一次SolidColorBrush.Color?即使SolidColorBrush继承自DependencyObject并且因此没有DataContext，它也可以工作.

dain is correct you can still bind to the DataContext which is created artificially, how often have you seen people bind to a SolidColorBrush.Color? It also works even though SolidColorBrush inherits from DependencyObject and hence has no DataContext.

请参见有关继承上下文的博客文章.

问题在于，由于这些行为是附加的，因此它们不会出现在逻辑树中，因此无论如何也不会继承DataContext.

The thing is that since the behaviours are attached, they do not appear in the logical tree and hence would not inherit a DataContext anyway.

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