Silverlight:如何接收继承的 DependencyProperty 中更改的通知 [英] Silverlight: How to receive notification of a change in an inherited DependencyProperty

问题描述

我有一个控件，它继承自(你猜对了)控件.我想在 FontSize 或 Style 属性更改时收到通知.在 WPF 中，我会通过调用 DependencyProperty.OverrideMetadata() 来做到这一点.当然，Silverlight 中没有这种有用的东西.那么，如何才能收到这些通知呢?

I have a control which inherits from (you guessed it) Control. I want to receive a notification whenever the FontSize or Style properties are changed. In WPF, I would do that by calling DependencyProperty.OverrideMetadata(). Of course, useful things like that have no place in Silverlight. So, how might one receive those kinds of notifications?

推荐答案

我认为这里有一个更好的方法.还是要看优劣.

I think here is a better way. Still need to see the pros and Cons.

 /// Listen for change of the dependency property
    public void RegisterForNotification(string propertyName, FrameworkElement element, PropertyChangedCallback callback)
    {

        //Bind to a depedency property
        Binding b = new Binding(propertyName) { Source = element };
        var prop = System.Windows.DependencyProperty.RegisterAttached(
            "ListenAttached"+propertyName,
            typeof(object),
            typeof(UserControl),
            new System.Windows.PropertyMetadata(callback));

        element.SetBinding(prop, b);
    }

现在，您可以调用 RegisterForNotification 来注册元素属性的更改通知，例如.

And now, you can call RegisterForNotification to register for a change notification of a property of an element, like .

RegisterForNotification("Text", this.txtMain,(d,e)=>MessageBox.Show("Text changed"));
RegisterForNotification("Value", this.sliderMain, (d, e) => MessageBox.Show("Value changed"));

在相同的http://amazedsaint.blogspot.com/2009/12/silverlight-listening-to-dependency.html

使用 Silverlight 4.0 测试版.

Using Silverlight 4.0 beta.

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