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社区首页 >问答首页 >由于正在进行树遍历，此时无法修改此节点的逻辑子节点是什么意思？

问由于正在进行树遍历，此时无法修改此节点的逻辑子节点是什么意思？
EN

Stack Overflow用户
提问于 2009-06-14 05:27:11
回答 8查看 10.6K关注 0票数 19

我在后台工作线程的DataContext方法中设置了一个对象的完成。由于某种原因，我收到一个错误消息：

此时无法修改此节点的逻辑子节点，因为正在进行指向Chart1.DataContext=allDates行的树审核。

正在进行的树漫步是什么意思？我也尝试过使用Dispatcher操作来做这个设置，结果也出现了同样的错误……有什么想法吗？谷歌对此错误消息没有任何反应。

导致这一问题的代码是Microsoft图表工具包的内部代码...我想知道我是不是发现了他们控制下的窃听器...

不使用Dispatcher：

代码语言：javascript
复制
 void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        ArticlesPerTimePeriodResult result = (ArticlesPerTimePeriodResult)e.Result;
        lvArticles.ItemsSource = result.DatesOfArticles;


        Chart1.DataContext = result.AllDates;
    }

使用Dispatcher：

代码语言：javascript
复制
 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：

代码语言：javascript
复制
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:
c#
wpf
backgroundworker
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/992241

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