WinUI 3中ProgressRing初始化时在Visual Studio 2022崩溃求助

问题场景 #

在WinUI3应用中实现点击按钮显示进度环的功能，使用单例模式封装ProgressRing控件，但控件初始化时触发崩溃，报错：

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

崩溃原因分析 #

1. 错误依赖UWP窗口API：WinUI3已不再推荐使用Window.Current和SystemNavigationManager.GetForCurrentView()这类UWP API，单例初始化时Window.Current可能尚未指向有效窗口实例，导致访问无效内存。
2. 控件树循环引用风险：将UserControl自身设置为Popup的Child，初始化阶段易造成控件树循环引用，触发内存访问保护机制。
3. 事件订阅时机错误：在构造函数中提前订阅窗口事件，此时窗口上下文未完全初始化，引发内存异常。

修复方案及代码调整 #

1. 重构ProgressRingControl实现 #

移除对UWP窗口API的依赖，调整Popup逻辑，在显示时动态绑定窗口尺寸：

ProgressRingControl.xaml.cs 修改后代码

using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Controls.Primitives;

namespace progress_sample
{
    public sealed partial class ProgressRingControl : UserControl
    {
        private Popup _popup;
        private static ProgressRingControl _instance;

        private ProgressRingControl()
        {
            this.InitializeComponent();
            _popup = new Popup { Child = this };
        }

        public static ProgressRingControl Instance
        {
            get
            {
                _instance ??= new ProgressRingControl();
                return _instance;
            }
        }

        public void ShowProgressRing()
        {
            if (_popup.IsOpen) return;

            var currentWindow = App.Current.Windows[0] as Window;
            if (currentWindow == null) return;

            // 匹配窗口尺寸
            this.Width = currentWindow.Bounds.Width;
            this.Height = currentWindow.Bounds.Height;

            // 订阅窗口尺寸变化
            currentWindow.SizeChanged += CurrentWindow_SizeChanged;

            IndeterminateProgress.IsActive = true;
            _popup.IsOpen = true;
        }

        private void CurrentWindow_SizeChanged(object sender, WindowSizeChangedEventArgs args)
        {
            var window = sender as Window;
            if (window != null)
            {
                this.Width = window.Bounds.Width;
                this.Height = window.Bounds.Height;
            }
        }

        public void HideProgressRing()
        {
            if (!_popup.IsOpen) return;

            IndeterminateProgress.IsActive = false;
            _popup.IsOpen = false;

            // 取消事件订阅，避免内存泄漏
            var currentWindow = App.Current.Windows[0] as Window;
            if (currentWindow != null)
            {
                currentWindow.SizeChanged -= CurrentWindow_SizeChanged;
            }
        }
    }
}

2. 验证App.xaml.cs窗口初始化 #

确保App类中正确初始化并持有主窗口引用：

using Microsoft.UI.Xaml;

namespace progress_sample
{
    public partial class App : Application
    {
        public App()
        {
            this.InitializeComponent();
        }

        protected override void OnLaunched(LaunchActivatedEventArgs args)
        {
            _mainWindow = new MainWindow();
            _mainWindow.Activate();
        }

        private Window _mainWindow;
    }
}

3. 保留原有MainWindow逻辑 #

MainWindow的XAML和后台代码无需修改，点击按钮的逻辑保持原样即可。

关键修改点说明 #

• 移除Window.Current和SystemNavigationManager相关代码，改用WinUI3原生的App.Current.Windows获取当前窗口。
• 将窗口相关操作延迟到ShowProgressRing方法中，确保窗口上下文已完全初始化。
• 仅在显示进度环时订阅窗口尺寸变化事件，隐藏时取消订阅，避免内存泄漏。

内容的提问来源于stack exchange，提问作者Sumnoon