19

我在后台工作线程的完成方法中设置对象的 DataContext。出于某种原因，我收到一条错误消息：

目前无法修改此节点的逻辑子节点，因为正在进行指向 Chart1.DataContext=allDates 行的树遍历。

a tree walk is in progress 是什么意思？我也尝试过使用 Dispatcher 操作来完成这个设置，并且给出了同样的错误......有什么想法吗？谷歌对此错误消息没有任何反应。

导致此问题的代码是 Microsoft 图表工具包的内部代码......我想知道我是否在他们的控制中发现了一个错误......

没有调度员：

 void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        ArticlesPerTimePeriodResult result = (ArticlesPerTimePeriodResult)e.Result;
        lvArticles.ItemsSource = result.DatesOfArticles;


        Chart1.DataContext = result.AllDates;
    }

与调度员：

 void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        ArticlesPerTimePeriodResult result = (ArticlesPerTimePeriodResult)e.Result;
        lvArticles.ItemsSource = result.DatesOfArticles;

        Dispatcher.BeginInvoke((Action<List<KeyValuePair<DateTime,int>>>)(delegate(List<KeyValuePair<DateTime,int>> allDates)
        {
            Chart1.DataContext = allDates;
        }), result.AllDates);

        //Chart1.DataContext = result.AllDates;
    }

错误：

System.Reflection.TargetInvocationException was unhandled
  Message="Exception has been thrown by the target of an invocation."
  Source="mscorlib"
  StackTrace:
       at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
       at System.Delegate.DynamicInvokeImpl(Object[] args)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
       at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.DispatcherOperation.InvokeImpl()
       at System.Threading.ExecutionContext.runTryCode(Object userData)
       at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
       at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.TranslateAndDispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Application.RunInternal(Window window)
       at NewsCluesWpf.App.Main() in C:\SoftwareInstall\VSProjects\NewsClues\NewsCluesWpf\obj\Debug\App.g.cs:line 0
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone()
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.InvalidOperationException
       Message="Cannot modify the logical children for this node at this time because a tree walk is in progress."
       Source="PresentationFramework"
       StackTrace:
            at System.Windows.FrameworkElement.AddLogicalChild(Object child)
            at System.Windows.Controls.UIElementCollection.InsertInternal(Int32 index, UIElement element)
            at System.Windows.Controls.DataVisualization.ObservableCollectionListAdapter`1.<>c__DisplayClass1.<OnCollectionChanged>b__0(T item, Int32 index)
            at System.Windows.Controls.DataVisualization.EnumerableFunctions.ForEachWithIndex[T](IEnumerable`1 that, Action`2 action)
            at System.Windows.Controls.DataVisualization.ObservableCollectionListAdapter`1.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedAction action, Object item, Int32 index)
            at System.Collections.ObjectModel.ObservableCollection`1.InsertItem(Int32 index, T item)
            at System.Windows.Controls.DataVisualization.ReadOnlyObservableCollection`1.InsertItem(Int32 index, T item)
            at System.Collections.ObjectModel.Collection`1.Insert(Int32 index, T item)
            at System.Windows.Controls.DataVisualization.AggregatedObservableCollection`1.<>c__DisplayClass14.<>c__DisplayClass16.<ChildCollectionCollectionChanged>b__f(ReadOnlyObservableCollection`1 that)
            at System.Windows.Controls.DataVisualization.ReadOnlyObservableCollection`1.Mutate(Action`1 action)
            at System.Windows.Controls.DataVisualization.AggregatedObservableCollection`1.<>c__DisplayClass14.<ChildCollectionCollectionChanged>b__e(T item, Int32 index)
            at System.Windows.Controls.DataVisualization.EnumerableFunctions.ForEachWithIndex[T](IEnumerable`1 that, Action`2 action)
            at System.Windows.Controls.DataVisualization.AggregatedObservableCollection`1.ChildCollectionCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedAction action, Object item, Int32 index)
            at System.Collections.ObjectModel.ObservableCollection`1.InsertItem(Int32 index, T item)
            at System.Collections.ObjectModel.Collection`1.Add(T item)
            at System.Windows.Controls.DataVisualization.Charting.Chart.AddAxisToChartArea(Axis axis)
            at System.Windows.Controls.DataVisualization.Charting.Chart.ActualAxesCollectionChanged(Object sender, NotifyCollectionChangedEventArgs e)
            at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
            at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedAction action, Object item, Int32 index)
            at System.Collections.ObjectModel.ObservableCollection`1.InsertItem(Int32 index, T item)
            at System.Windows.Controls.DataVisualization.UniqueObservableCollection`1.InsertItem(Int32 index, T item)
            at System.Collections.ObjectModel.Collection`1.Add(T item)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeriesWithAxes.GetAxes(DataPoint firstDataPoint, Func`2 independentAxisPredicate, Func`1 independentAxisFactory, Func`2 dependentAxisPredicate, Func`1 dependentAxisFactory)
            at System.Windows.Controls.DataVisualization.Charting.AreaSeries.GetAxes(DataPoint firstDataPoint)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeriesWithAxes.GetAxes()
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeriesWithAxes.OnDataPointsChanged(IList`1 newDataPoints, IList`1 oldDataPoints)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSingleSeriesWithAxes.OnDataPointsChanged(IList`1 newDataPoints, IList`1 oldDataPoints)
            at System.Windows.Controls.DataVisualization.Charting.LineAreaBaseSeries`1.OnDataPointsChanged(IList`1 newDataPoints, IList`1 oldDataPoints)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeries.LoadDataPoints(IEnumerable newItems, IEnumerable oldItems)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeries.Refresh()
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeries.OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)
            at System.Windows.Controls.DataVisualization.Charting.DataPointSeries.OnItemsSourceChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
            at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
            at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
            at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
            at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)
            at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp)
            at System.Windows.Data.BindingExpression.Invalidate(Boolean isASubPropertyChange)
            at System.Windows.Data.BindingExpression.TransferValue(Object newValue, Boolean isASubPropertyChange)
            at System.Windows.Data.BindingExpression.Activate(Object item)
            at System.Windows.Data.BindingExpression.HandlePropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
            at System.Windows.Data.BindingExpression.OnPropertyInvalidation(DependencyObject d, DependencyPropertyChangedEventArgs args)
            at System.Windows.DependentList.InvalidateDependents(DependencyObject source, DependencyPropertyChangedEventArgs sourceArgs)
            at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
            at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)
            at System.Windows.TreeWalkHelper.OnInheritablePropertyChanged(DependencyObject d, InheritablePropertyChangeInfo info)
            at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
            at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
            at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
            at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
            at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
            at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
            at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
            at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
            at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
            at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
            at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
            at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
            at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
            at System.Windows.DescendentsWalker`1.WalkLogicalChildren(FrameworkElement feParent, FrameworkContentElement fceParent, IEnumerator logicalChildren)
            at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
            at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
            at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
            at System.Windows.DescendentsWalker`1.WalkFrameworkElementLogicalThenVisualChildren(FrameworkElement feParent, Boolean hasLogicalChildren)
            at System.Windows.DescendentsWalker`1.IterateChildren(DependencyObject d)
            at System.Windows.DescendentsWalker`1.StartWalk(DependencyObject startNode, Boolean skipStartNode)
            at System.Windows.TreeWalkHelper.InvalidateOnInheritablePropertyChange(FrameworkElement fe, FrameworkContentElement fce, InheritablePropertyChangeInfo info, Boolean skipStartNode)
            at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
            at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
            at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)
            at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, OperationType operationType, Boolean isInternal)
            at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
            at System.Windows.FrameworkElement.set_DataContext(Object value)
            at NewsCluesWpf.ArticlesPerDay.<bg_RunWorkerCompleted>b__1(List`1 allDates) in C:\SoftwareInstall\VSProjects\NewsClues\NewsCluesWpf\ArticlesPerDay.xaml.cs:line 72
       InnerException:
4

9 回答 9

10

解决了！

问题：每次更改某些数据时，我都想在 GUI 上更新我的图表。

 myChart.DataContext = MTFdata;

当我这样做时，我收到错误：此时无法修改此节点的逻辑子节点，因为正在进行树遍历

我是如何解决的：

插入这个：

 <chartingToolkit:LineSeries   DependentValuePath="Key" 
                                                    IndependentValuePath="Value" 
                                                    ItemsSource="{Binding}"
                                                    IsSelectionEnabled="False"
                                                                             >

用这个：

 <chartingToolkit:LineSeries   DependentValuePath="Key" 
                                                    IndependentValuePath="Value" 
                                                    ItemsSource="{Binding}"
                                                    DataContext="{Binding}"
                                                    IsSelectionEnabled="False"
                                                                             >

同时使用ItemsSource="{Binding}"和DataContext="{Binding}"

希望这可以帮助！

于 2014-08-17T12:23:41.297 回答
8

在玩了更多之后，我认为这是 Silverlight 图表工具包中的一个错误。

以下代码会导致可重现的崩溃。

int runCount = 0;
        private void bindChart(string searchString)
        {
           List<KeyValuePair<DateTime, int>> dataEmpty = new List<KeyValuePair<DateTime, int>>();

            List<KeyValuePair<DateTime, int>> dataFilled = new List<KeyValuePair<DateTime, int>>();
            dataFilled.Add(new KeyValuePair<DateTime, int>(DateTime.Today, 1));
            if (runCount == 0)
            {
                Chart1.DataContext= dataEmpty;
            }
            else
            {
                Chart1.DataContext = dataFilled;
            }
            runCount++;

        }

XAML：

<charting:Chart Grid.Row="0"
    Title="Title"
    LegendTitle="Legend" Name="Chart1" Grid.RowSpan="2">
            <charting:AreaSeries ItemsSource="{Binding}"

                                       DependentValuePath="Value"

                                       IndependentValuePath="Key"

                                       Background="Red" />


        </charting:Chart>

这将在第二次调用 bindChart 时失败。

于 2009-06-14T06:15:48.847 回答
2

嘿嘿，

我刚刚遇到错误，并且也修复了它。设置数据上下文时也会出现该错误。

我发现我在设置了数据上下文的列表上有一个 selectionchanged-subscription。在这个 selectionchanged 中，我正在更改另一个具有通知支持的属性，该属性上有一个可视元素绑定。

通过使用调度程序设置属性解决了该问题。

因此，请尝试查找有关更改的订阅...

于 2009-08-25T13:01:59.820 回答
0

显然，正在执行一些操作，在使用时更改集合。这是一个很大的禁忌。

在不进一步分析代码的情况下，我只能这么说。

于 2009-06-14T05:36:16.353 回答
0

这是我对它的研究。

WaybackMachine 上所述链接的镜像。

它是在进行树遍历时由 FrameworkElement 和 FrameworkContentElement 中的 Add/RemoveLogicalChild 方法引发的 WPF 异常。它的无聊细节在博客文章中，但最重要的是，您只能测试它然后在它发生的地方捕获它。异常应该是相对罕见的情况。

于 2011-03-16T09:47:50.167 回答
0

DataContext而不是通过可观察的集合重置重用也可以......

    int runCount = 0;

    private void bindChart()
    {
        ObservableCollection<KeyValuePair<DateTime, int>> data = new ObservableCollection<KeyValuePair<DateTime, int>>();

        if (runCount == 0)
        {
            this.DataContext = dataEmpty;
        }
        else
        {
            var de = this.DataContext as ObservableCollection<KeyValuePair<DateTime, int>>;
            de.Clear();
            for (var i = 0; i < (new Random(DateTime.Now.Second)).Next(100); i++)
            {
                de.Add(new KeyValuePair<DateTime, int>(DateTime.Today.AddDays(i), i));
            }
        }

        runCount++;
    }
于 2011-09-19T10:16:18.900 回答
0

我刚刚在 WPF 图表工具包中遇到了这个问题。每个人都说不要绑定到 DataContext 并直接绑定到 ItemsSource 但我已经绑定到 ItemsSource 并且仍然出现错误。在我的情况下，我绑定到SelectedItemListBox 或 TreeView。我唯一能做的就是手动绑定到ItemsSourceSelectedItemChanged() 事件触发的时间。

private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
    if (TreeView.SelectedItem != null)
        LineSeries.ItemsSource = (TreeView.SelectedItem as MyObject).Items;
}
于 2014-05-09T19:59:52.100 回答
0

当父控件（AvalonDock）触发子用户控件重新加载时，我遇到了这个问题：用户控件将触发其“Loaded”事件，我的应用程序将崩溃。

我从用户控件中删除了 Loaded 事件处理程序，并改用 Initialized 事件。这解决了我的问题，虽然我不完全确定为什么。

于 2016-12-06T15:50:48.187 回答
-1

我也有同样的问题。我没有使用任何后台线程。我只有一个滑块，在滑块的 ValueChanged 事件中，我正在重新计算和重置 DataContext。

例如，燃尽图。随着初始值的变化，图形会自动更新（本质上是线系列的 Y 轴）。

更改数据上下文在 silverlight 3 的 beta 版本中有效。在发布版本中无效。以上关于设置 (Chart1.Series[0] as DataPointSeries).ItemsSource 的评论对我有用

于 2009-07-16T06:22:11.517 回答