我在后台工作线程的已完成方法中设置对象的DataContext。出于某种原因，我收到一个错误说：
此时无法修改此节点的逻辑子节点，因为正在进行树步行指向Chart1.DataContext = allDates行。
树木行走的意义何在？我已经尝试使用Dispatcher操作执行此设置，并且出现相同的错误...任何想法？谷歌在这个错误消息上没有任何结果。
代码导致这是微软Charting工具包内部的......我想知道我是否在他们的控制中发现了一个错误......
没有Dispatcher：
void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
ArticlesPerTimePeriodResult result = (ArticlesPerTimePeriodResult)e.Result;
lvArticles.ItemsSource = result.DatesOfArticles;
Chart1.DataContext = result.AllDates;
}
使用Dispatcher：
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:
答案 0 :(得分：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>
第二次调用bindChart时会失败。
答案 1 :(得分：8)
<强>解决！
问题：我想在每次更改某些数据时更新GUI上的图表。
myChart.DataContext = MTFdata;
当我这样做时，我得到错误：此时无法修改此节点的逻辑子节点，因为正在进行树步行
我是如何解决的：
注意到这一点：
<chartingToolkit:LineSeries DependentValuePath="Key"
IndependentValuePath="Value"
ItemsSource="{Binding}"
IsSelectionEnabled="False"
>
使用此：
<chartingToolkit:LineSeries DependentValuePath="Key"
IndependentValuePath="Value"
ItemsSource="{Binding}"
DataContext="{Binding}"
IsSelectionEnabled="False"
>
同时使用ItemsSource="{Binding}"和DataContext="{Binding}"
希望这有帮助！
答案 2 :(得分：2)
Hej，
我刚刚遇到错误，并修复了它。 设置datacontext时也会出现错误。
我发现我在设置了datacontext的列表上有一个selectionchanged-subscription。在这个选择中，我改变了另一个带有通知支持的属性，该属性上有一个可视元素绑定。
使用调度程序设置属性解决了问题。
因此，请尝试查找有关更改的订阅...
答案 3 :(得分：0)
显然，正在进行一些操作，即在使用它时更改集合。这是一个很大的禁忌。
如果不进一步分析代码，那就是我所能说的。
答案 4 :(得分：0)
当树步行正在进行时，它是由FrameworkElement和FrameworkContentElement中的Add / RemoveLogicalChild方法抛出的WPF异常。它的枯燥细节在博客文章中，但最重要的是你不能做更多的测试，然后抓住它发生的地方。例外情况应该是相对罕见的。
答案 5 :(得分：0)
而不是重置DataContext通过可观察集合重用也可以...
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++;
}
答案 6 :(得分：0)
我刚刚遇到WPF图表工具包的这个问题。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并仍然出错。在我的例子中，我绑定到ListBox或TreeView的SelectedItem。我唯一可以工作的是当SelectedItemChanged（）事件触发时手动绑定到ItemsSource。
private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
if (TreeView.SelectedItem != null)
LineSeries.ItemsSource = (TreeView.SelectedItem as MyObject).Items;
}
答案 7 :(得分：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：用户控件将触发其加载＆＃34;加载＆＃34;事件和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，并使用了Initialized事件。这解决了我的问题，虽然我不完全确定原因。
答案 8 :(得分：-1)
我有同样的问题。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，我正在重新计算并重置DataContext。
例如，烧毁图表。随着初始值的变化，图表会自动更新（基本上是系列的Y轴）。
更改在silverlight 3的测试版中工作的datacontext。在发行版中不起作用。以上关于设置的注释（Chart1.Series [0]为DataPointSeries）.ItemsSource适合我