UWP用户控件：集合已更改绑定依赖项属性的事件

Question

当我调用Generate()时，不会触发与ObservableCollection（X）关联的事件。

我做错了什么？

代码：

  

MyControl.xaml.cs

 public ObservableCollection<double> X
    {
        get { return (ObservableCollection<double>)GetValue(XProperty); }
        set { SetValue(XProperty, value); }
    }

    public static readonly DependencyProperty XProperty =
        DependencyProperty.Register(
            "X", typeof(ObservableCollection<double>),
            typeof(MyControl), 
            new PropertyMetadata(
                new ObservableCollection<double>(),
                new PropertyChangedCallback(OnXChanged)));

   private static void OnXChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            var control = sender as MyControl;

            // DoSomething
        }

  

使用MyControl的XAML随机页面：

 <local:MyControl
            Title="Test"
            X="{Binding TestX, Mode=TwoWay}"
            />

  

该页面的.cs

   public sealed partial class MainPage : Page
    {
    public ObservableCollection<double> TestX { get; set; }
    private static Random rand_ = new Random();

    public MainPage()
    {
        this.InitializeComponent();
        TestX = new ObservableCollection<double>();
    }

    private void Generate()
        {
            TestX.Clear();

            for (int i = 0; i < 100; ++i)
            {
                TestX.Add(rand_.Next(1, 100));
            }
        }
   ....
 }

请注意，我在输出窗口中看不到任何BindingExpression错误。

更新

我注意到如果在页面中这样做，它可以工作：

TestX = new ObservableCollection<double>();
this.MyUserControlInstance.X = TestX;