wp7和依赖属性：onChanged和onRead？

Question

我想要构建一个wp7控件，所以我写它并且一切顺利，但问题是我可以拦截写（请参阅onItemsSourcePropertyChanged）但不读取我想更好地解释：

public static readonly
DependencyProperty ItemsSourceProperty=
         DependencyProperty.Register(
             "ItemsSource",
             typeof(ObservableCollection<ObjWithDesc>),
             typeof(HorizontalListBox),
             new PropertyMetadata(OnItemsSourcePropertyChanged)
         );




    static void OnItemsSourcePropertyChanged(DependencyObject obj,DependencyPropertyChangedEventArgs e)
{
         ((HorizontalListBox) obj).OnItemsSourcePropertyChanged(e);
}

当我使用SetValue（dp，..）但是没有onItemsSourcePropertyRead时会调用OnItemsSourcePropertyChanged？当我使用GetValue（）时调用？感谢

Answer 1

您可以将OnRead操作添加到支持字段的getter中：

    public string ItemsSource
    {
        get 
        { 
            // Call your OnRead functionality here!
            return (string)GetValue(ItemsSourceProperty); 
        }

        set 
        { 
            SetValue(ItemsSourceProperty, value);
        }
    }