wpf - 在 WPF 中跟踪 AccessViolationException

Question

我编写了一个 WPF 应用程序，它使用许多 Frame 控件来查看相机源。部署后，它非常随机地崩溃(从 2 小时到 16 小时以上)，我在事件日志中连续看到这些:

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.Run() at System.Windows.Application.RunDispatcher(Object ignore) at System.Windows.Application.RunInternal(Window window) at System.Windows.Application.Run(Window window) at System.Windows.Application.Run() at Status_Station_client.MainClass.Main()

Faulting application status station client.exe, version 1.0.0.0, stamp 4ad0faa5, faulting module msvfw32.dll, version 5.1.2600.2180, stamp 41109753, debug? 0, fault address 0x00002642.

关于如何追踪这一点的任何想法？网页确实包含 ActiveX 控件，所以第一个猜测是那里有问题。

我无法在 Debug模式下跟踪这一点。我想尝试的另一件事是从导航调用中吞下异常，但我不确定这是否是明智之举:

try
{
    if (Frame1 != null)
        Frame1.Source = new Uri(uriWithResolution);
}
catch (AccessViolationException ex)
{
    // log message
}

编辑:这里有更多源代码，我对错误在哪里(即抛出异常的位置)感到困惑

矩阵 View .cs:

public partial class MatrixView : Window
{
    System.Timers.Timer timer;
    int pageNumber = 0;
    IEnumerable<List<CameraInfo>> _cameraList;
    GlobalSettings _globalSettings;
    Screen _screen;

    public MatrixView(List<CameraInfo> cameras, int pageFlipInterval, int camerasPerPage, GlobalSettings globalSettings, Screen screen)
    {
        InitializeComponent();
        _globalSettings = globalSettings;
        _screen = screen;
        _cameraList = Partition<CameraInfo>(cameras, camerasPerPage);

        this.Dispatcher.UnhandledException += new DispatcherUnhandledExceptionEventHandler(Dispatcher_UnhandledException);

        displayCameras();

        timer = new System.Timers.Timer(pageFlipInterval * 1000); // interval (in seconds) * 1000 ms / s
        timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);
        timer.Enabled = true;

        this.KeyUp += new System.Windows.Input.KeyEventHandler(MatrixView_KeyUp);

        if (globalSettings.FullScreenOnLoad)
        {
            this.WindowStyle = WindowStyle.None;
        }
    }

    void MatrixView_KeyUp(object sender, System.Windows.Input.KeyEventArgs e)
    {
        if (this.WindowStyle == WindowStyle.None)
        {
            if (e.Key == Key.F11 || e.Key == Key.Escape)
            {
                this.WindowStyle = WindowStyle.SingleBorderWindow;

            }
        }
        else
        {
            if (e.Key == Key.F11)
            {
                this.WindowStyle = WindowStyle.None;
            }
        }
        this.WindowState = WindowState.Maximized;

    }

    void timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        this.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new ThreadStart(delegate()
        {
            displayCameras();

        }));

    }

    void Dispatcher_UnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
    {
        EventLog.WriteEntry("Matrix Monitor", string.Format("Unhandled exception from Matrix Dispatcher\r\nMessage: {0}\r\nSource: {1}\r\nInnerException: {2}\r\nStack Trace: {3}\r\nFull String: {4}", e.Exception.Message, e.Exception.Source, e.Exception.InnerException, e.Exception.StackTrace, e.Exception.ToString()));
        e.Handled = true;
    }

    private void displayCameras()
    {
        foreach (var child in uniformGrid1.Children)
        {
            FrameTimer c = child as FrameTimer;
            if (c != null)
            {
                c.Dispose();
                c = null;
            }
        }
        GC.Collect();
        GC.WaitForPendingFinalizers();

        uniformGrid1.Children.Clear();
        List<CameraInfo> camerasInPage = _cameraList.ElementAt(pageNumber);
        int numCameras = camerasInPage.Count;

        int sqrtOfCameras = (int) Math.Sqrt(numCameras);
        double height = _screen.Bounds.Height / sqrtOfCameras;
        double width = _screen.Bounds.Width / sqrtOfCameras;
        foreach (CameraInfo camera in camerasInPage)
        {
            uniformGrid1.Children.Add(new FrameTimer(camera, _globalSettings, height, width));
        }
        pageNumber++;
        if (pageNumber >= _cameraList.Count<List<CameraInfo>>())
        {
            pageNumber = 0;
        }



    }
    public static IEnumerable<List<T>> Partition<T>(IList<T> source, int size)
    {
        int remainder = source.Count % size == 0 ? 0 : 1;
        for (int i = 0; i < (source.Count / size) + remainder; i++)        
            yield return new List<T>(source.Skip(size * i).Take(size)); 
    }
}

帧定时器.cs:

public partial class FrameTimer : UserControl, IDisposable
{

    System.Timers.Timer timer;
    string _uri;
    string _noImageUrl;
    bool? _successState = null;
    GlobalSettings _globalSettings;
    CameraInfo _camera;
    Ping ping;
    double _height;
    double _width;

    public FrameTimer(CameraInfo camera, GlobalSettings globalSettings, double height, double width)
    {
        InitializeComponent();

        _noImageUrl = AppDomain.CurrentDomain.BaseDirectory + "noImage.jpg";
        _globalSettings = globalSettings;
        _camera = camera;
        _height = height;
        _width = width;

        _uri = string.Format("http://{0}:{1}/LiveView.aspx?camera={2}", globalSettings.ServerIPAddress, globalSettings.ServerPort, camera.camName);
        this.Dispatcher.UnhandledException += new DispatcherUnhandledExceptionEventHandler(Dispatcher_UnhandledException);

        setUrl();

        timer = new System.Timers.Timer(_globalSettings.PingInterval * 1000); 
        timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
        timer.Enabled = true;

    }

    void Dispatcher_UnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
    {
        EventLog.WriteEntry("Matrix Monitor", string.Format("Unhandled exception from Frame Dispatcher\r\nMessage: {0}\r\nSource: {1}\r\nInnerException: {2}\r\nStack Trace: {3}\r\nFull String: {4}", e.Exception.Message, e.Exception.Source, e.Exception.InnerException, e.Exception.StackTrace, e.Exception.ToString()));
        e.Handled = true;
    } 


    void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        this.Dispatcher.BeginInvoke(DispatcherPriority.Send, new ThreadStart(delegate()
            {
                setUrl();
            }));
    }

    private void setUrl()
    {
        ping = new Ping();
        ping.PingCompleted += new PingCompletedEventHandler(ping_PingCompleted);
        videoChecks checks = new videoChecks();

        string ipAddressToUse = checks.isIPInternal(_camera.camIP) ? _camera.camIP : _camera.camExtIP;
        ping.SendAsync(ipAddressToUse, 1000, null);
    }

    void ping_PingCompleted(object sender, PingCompletedEventArgs e)
    {
        try
        {
            if (e.Reply.Status == IPStatus.Success)
            {
                if (_successState == null || _successState == false)
                {
                    _successState = true;
                    string uriWithResolution = string.Format("{0}&res={1}x{2}&header=0", _uri, (int)_width, (int)_height);

                    if (Frame1 != null)
                        Frame1.Source = new Uri(uriWithResolution);
                }
            }
            else
            {
                if (_successState == null || _successState == true)
                {
                    _successState = false;
                    Image1.Source = new BitmapImage(new Uri(_noImageUrl));
                }
            }
        }
        catch (ObjectDisposedException ex)
        {
            Dispose();
        }
        finally
        {
            ((IDisposable)sender).Dispose();
        }

    }

    #region IDisposable Members

    public void Dispose()
    {
        if (timer != null)
        {
            timer.Elapsed -= new System.Timers.ElapsedEventHandler(timer_Elapsed);
            timer.Enabled = false;
            timer.Dispose();
            timer = null;
        }

        Frame1.Source = null;

        if (ping != null)
        {
            ping.PingCompleted -= new PingCompletedEventHandler(ping_PingCompleted);
            ((IDisposable)ping).Dispose();
            ping = null;
        }
    }

    #endregion
}

Answer 1

如果您查看堆栈跟踪底部的故障模块，您将看到 msvfw32.dll。这不是 WPF 使用的 DLL，所以我假设它来自您正在加载的网页中的一些 active-x。我更加确信这一点，因为您的代码暗示了一些处理相机/视频的内容，而 msvfw32 处理了视频(它也很老了!!)。它出现在 Dispatcher 循环中，因为 Dispatcher 还处理 Win32 消息循环，最终由所谓的 activex 使用。

另外，尝试检查 exception here , 也许你可以设置参数 Handled=true