Xaml uwp：数据绑定编程问题

我正在使用uwp进行开发，在数据绑定方面遇到了一个问题。我有一个listView，其中填充了一个名为PlayLeftOption类的自定义面板元素。该类继承继承FrameworkElement类属性及其方法的面板类属性，因此我有一个可用的SetBinding方法。 现在我试图绑定height值（它等于其他元素），所以我在其他extern单例类中创建了一个静态属性，称为PerformanceItemHeight。 因为我需要动态地填充listview，所以我试图在构造函数中绑定该值，但它不起作用。 这是构造函数中的代码：

    public PlaylistLeftOption()
    {
        mainGrid.Background = new SolidColorBrush(Colors.Red);
        mainGrid.BorderBrush = new SolidColorBrush(Colors.Black);
        mainGrid.BorderThickness = new Thickness(0.5,0.25,0.5,0.25);

        WidthVal = 200;
        HeightVal = 50;

        var myBinding = new Binding();
        myBinding.Source = PerformanceLayout.Instance.PerformanceItemHeight;
        myBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
        myBinding.Mode = BindingMode.TwoWay;
        SetBinding(HeightValProperty, myBinding);

        Children.Add(mainGrid);
    }

这就是财产：

     public static readonly DependencyProperty HeightValProperty = DependencyProperty.Register(
      "HeightVal",
      typeof(double),
      typeof(PlaylistLeftOption),
      new PropertyMetadata(50)
    );

    public double HeightVal
    {
        get => (double)GetValue(HeightValProperty);
        set
        {
            SetValue(HeightValProperty, value);
            Height = HeightVal;
            mainGrid.Height = HeightVal;
            globalSize.Height = HeightVal;
        }
    }

这是PerformanceItemHeight的代码：

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        // Raise the PropertyChanged event, passing the name of the property whose value has changed.
        this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    private double _performanceItemHeight = 50;
    public double PerformanceItemHeight {
        get => _performanceItemHeight;
        set {
            _performanceItemHeight = value;
            this.OnPropertyChanged();
        }
    }

为什么通过xaml它可以工作？ 我试着通过xaml在listview中添加PlayLeftOption项，没问题！

---

谢谢

通过测试，

HeightVal

的绑定在XAML中工作，

HeightVal

的绑定在代码隐藏中不工作。您可以在文档的实现包装器部分中看到原因，该部分指出包装器实现应该只执行GetValue和SetValue操作。否则，当通过XAML设置属性与通过代码设置属性时，您将获得不同的行为

您可以添加一个通知来主动通知

HeightVal

的更改

例如：

public static readonly DependencyProperty HeightValProperty = DependencyProperty.Register(
  "HeightVal",
  typeof(double),
  typeof(PlaylistLeftOption),
  new PropertyMetadata(100, new PropertyChangedCallback(OnHeightValChanged))
);
private static void OnHeightValChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    PlaylistLeftOption playlistLeftOption = d as PlaylistLeftOption;
    if(playlistLeftOption != null)
    {
        var height = (Double)e.NewValue;
        playlistLeftOption.HeightVal = height;
    }
}

并更改Bing代码，如下所示：

var myBinding = new Binding();
myBinding.Source = PerformanceLayout.Instance;
myBinding.Path = new PropertyPath("PerformanceItemHeight");
myBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
myBinding.Mode = BindingMode.TwoWay;
SetBinding(HeightValProperty, myBinding);

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杨古：非常感谢！它工作正常！如果答案解决了您的问题，请将其视为已接受