WPF UI AddIn 未更新其所需的大小

Question

我有一个应用程序，它通过 INativeHandleContract 从不同的 AppDomain 获取其 UI 控件之一。当控件的大小更改时，主机中的 FrameworkElement 不会获得更新的大小。我想知道是否有任何方法可以解决这个问题。

下面是示例代码（XAML 只是一个空白窗口）：

public partial class Window1 : Window
{
    private StackPanel m_stackPanel;
    private Expander m_expander;

    private UIElement m_expanderAddIn;

    public Window1()
    {
        InitializeComponent();

        m_stackPanel = new StackPanel { Orientation = Orientation.Vertical };
        m_stackPanel.Background = Brushes.Red;
        m_expander = new Expander
                         {
                             ExpandDirection = ExpandDirection.Right,
                             Background=Brushes.Blue,
                             IsExpanded=true,
                         };
        m_expander.Expanded += CheckStuff;
        m_expander.Collapsed += CheckStuff;

        Rectangle r = new Rectangle {Fill = Brushes.LightGray, Height = 300, Width = 300};

        m_expander.Content = r;

        m_expanderAddIn = FrameworkElementAdapters.ContractToViewAdapter(FrameworkElementAdapters.ViewToContractAdapter(m_expander));

        m_stackPanel.Children.Add(m_expanderAddIn);

        Content = m_stackPanel;
    }

    private void CheckStuff(object sender, RoutedEventArgs e)
    {
        Debug.WriteLine("Expander: " + m_expander.DesiredSize);
        Debug.WriteLine("Add in: " + m_expanderAddIn.DesiredSize);
        Debug.WriteLine("Stack Panel: " + m_stackPanel.DesiredSize);
    }
}

当您展开和折叠 Expander 时，您会期望 StackPanel 的高度发生变化，但事实并非如此。任何想法都会有用，谢谢。

Answer 1

这真的很奇怪，我不知道为什么会这样。这可能只是重现您的问题的一个小例子，所以也许这对您没有多大帮助，但我让您的示例进行了 3 个更改。

1. 将 Expander 包装在“虚拟”StackPanel 中，并将其用作 m_expanderAddIn 的根元素。这解决了扩展器的高度问题。
2. 将 m_expanderAddIn 的类型从 UIElement 更改为 FrameworkElement
3. 将 m_expanderAddIn 的高度绑定到 m_expander

Code的 ActualHeight

public partial class Window1 : Window
{
    private StackPanel m_stackPanel;
    private Expander m_expander;

    private FrameworkElement m_expanderAddIn;

    public Window1()
    {
        InitializeComponent();

        m_stackPanel = new StackPanel { Orientation = Orientation.Vertical };
        m_stackPanel.Background = Brushes.Red;
        m_expander = new Expander
                         {
                             ExpandDirection = ExpandDirection.Right,
                             Background=Brushes.Blue,
                             IsExpanded=true,
                         };
        m_expander.Expanded += CheckStuff;
        m_expander.Collapsed += CheckStuff;

        Rectangle r = new Rectangle {Fill = Brushes.LightGray, Height = 300, Width = 300};

        m_expander.Content = r;
        StackPanel stackPanel = new StackPanel();
        stackPanel.Children.Add(m_expander);

        m_expanderAddIn = FrameworkElementAdapters.ContractToViewAdapter(FrameworkElementAdapters.ViewToContractAdapter(stackPanel));

        Binding binding = new Binding("ActualHeight");
        binding.Source = m_expander;
        m_expanderAddIn.SetBinding(FrameworkElement.HeightProperty, binding);

        m_stackPanel.Children.Add(m_expanderAddIn);

        Content = m_stackPanel;
    }

    private void CheckStuff(object sender, RoutedEventArgs e)
    {
        Debug.WriteLine("Expander: " + m_expander.DesiredSize);
        Debug.WriteLine("Add in: " + m_expanderAddIn.DesiredSize);
        Debug.WriteLine("Stack Panel: " + m_stackPanel.DesiredSize);
    }
}