WPF ObservableCollection.Remove引发NullReferenceException

调用remove操作的代码正常工作，这是我第一次收到NullReferenceException。我试图弄清楚我是否做了错事，是否可以避免异常，使软件更加防弹

相对而言，System.Windows.DegentSwalker`1.WalkFrameworkElementLogicalTheVisualChildren调用的数量相对较大，似乎也有点古怪

任何帮助都将不胜感激

OS:6.1.7600.0 .NET:4.0.30319.225

堆栈：

at System.Windows.DependencyPropertyChangedEventArgs.get_OldValue()
at System.Windows.Controls.Control.OnTemplateChanged(DependencyObject d, 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, Boolean coerceWithCurrentValue, OperationType operationType)
at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp)
at System.Windows.StyleHelper.InvalidateContainerDependents(DependencyObject container, FrugalStructList`1_ exclusionContainerDependents, FrugalStructList`1_ oldContainerDependents, FrugalStructList`1_ newContainerDependents)
at System.Windows.StyleHelper.DoStyleInvalidations(FrameworkElement fe, FrameworkContentElement fce, Style oldStyle, Style newStyle)
at System.Windows.StyleHelper.UpdateStyleCache(FrameworkElement fe, FrameworkContentElement fce, Style oldStyle, Style newStyle, Style_ styleCache)
at System.Windows.FrameworkElement.OnStyleChanged(DependencyObject d, 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, Boolean coerceWithCurrentValue, OperationType operationType)
at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp)
at System.Windows.FrameworkElement.UpdateStyleProperty()
at System.Windows.FrameworkElement.InvalidateTreeDependentProperties(TreeChangeInfo parentTreeState, Boolean isSelfInheritanceParent)
at System.Windows.FrameworkElement.OnAncestorChangedInternal(TreeChangeInfo parentTreeState)
at System.Windows.TreeWalkHelper.OnAncestorChanged(DependencyObject d, TreeChangeInfo info)
at System.Windows.DescendentsWalker`1._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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._VisitNode(DependencyObject d)
at MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1._VisitNode(DependencyObject d)
at System.Windows.DescendentsWalker`1.VisitNode(FrameworkElement fe)
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 MS.Internal.PrePostDescendentsWalker`1.StartWalk(DependencyObject startNode, Boolean skipStartNode)
at System.Windows.TreeWalkHelper.InvalidateOnTreeChange(FrameworkElement fe, FrameworkContentElement fce, DependencyObject parent, Boolean isAddOperation)
at System.Windows.FrameworkElement.OnVisualParentChanged(DependencyObject oldParent)
at System.Windows.Controls.ListBoxItem.OnVisualParentChanged(DependencyObject oldParent)
at System.Windows.Media.Visual.FireOnVisualParentChanged(DependencyObject oldParent)
at System.Windows.Media.Visual.RemoveVisualChild(Visual child)
at System.Windows.Media.VisualCollection.DisconnectChild(Int32 index)
at System.Windows.Media.VisualCollection.RemoveRange(Int32 index, Int32 count)
at System.Windows.Controls.UIElementCollection.RemoveRangeInternal(Int32 index, Int32 count)
at System.Windows.Controls.VirtualizingStackPanel.RemoveChildRange(GeneratorPosition position, Int32 itemCount, Int32 itemUICount)
at System.Windows.Controls.VirtualizingStackPanel.OnItemsRemove(ItemsChangedEventArgs args)
at System.Windows.Controls.VirtualizingStackPanel.OnItemsChanged(Object sender, ItemsChangedEventArgs args)
at System.Windows.Controls.VirtualizingPanel.OnItemsChangedInternal(Object sender, ItemsChangedEventArgs args)
at System.Windows.Controls.Panel.OnItemsChanged(Object sender, ItemsChangedEventArgs args)
at System.Windows.Controls.ItemContainerGenerator.OnItemRemoved(Object item, Int32 itemIndex)
at System.Windows.Controls.ItemContainerGenerator.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Windows.Controls.ItemContainerGenerator.System.Windows.IWeakEventListener.ReceiveWeakEvent(Type managerType, Object sender, EventArgs e)
at System.Windows.WeakEventManager.DeliverEventToList(Object sender, EventArgs args, ListenerList list)
at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
at System.Collections.Specialized.CollectionChangedEventManager.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Collections.Specialized.NotifyCollectionChangedEventHandler.Invoke(Object sender, NotifyCollectionChangedEventArgs e)
at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Controls.ItemCollection.System.Windows.IWeakEventListener.ReceiveWeakEvent(Type managerType, Object sender, EventArgs e)
at System.Windows.WeakEventManager.DeliverEventToList(Object sender, EventArgs args, ListenerList list)
at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
at System.Collections.Specialized.CollectionChangedEventManager.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Windows.Data.CollectionView.OnCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Data.ListCollectionView.ProcessCollectionChangedWithAdjustedIndex(NotifyCollectionChangedEventArgs args, Int32 adjustedOldIndex, Int32 adjustedNewIndex)
at System.Windows.Data.ListCollectionView.ProcessCollectionChanged(NotifyCollectionChangedEventArgs args)
at System.Windows.Data.CollectionView.OnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs args)
at System.Collections.ObjectModel.ObservableCollection`1.OnCollectionChanged(NotifyCollectionChangedEventArgs e)
at System.Collections.ObjectModel.ObservableCollection`1.RemoveItem(Int32 index)
at System.Collections.ObjectModel.Collection`1.Remove(T item)

---

我注意到在堆栈跟踪中有许多对OnPropertyChanged的调用，这表明代码正在触发许多PropertyChanged更改事件。如果您在代码中的某个地方持有对ObservableCollection中某个对象的引用，那么如果您的代码试图使用该对象，则可以获得NullReferenceException

因为您指出这是不常见的，所以我猜测删除的项是基于堆栈跟踪中XAML（查看InvalidateOnTreeChange）中的一个控件中的选定项引用的

我在这里包含了一个代码片段，它显示了对选定项的引用如何引发NullReferenceException。在我的示例中，我有一个DataGrid，它绑定到客户对象的ObservableCollection，并跟踪其所选项目。当代码从ObservableCollection中删除所选客户时，代码将触发PropertyChanged事件，导致DataGrid刷新其所选项目，该项目现在为null。在本例中，由于我尝试更新所选项目的属性，因此得到了NullReferenceException。我确信您的代码更复杂，但我希望这会有所帮助

<!--  displays a list of customers and tracks the selected customer  -->
<DataGrid ItemsSource="{Binding Customers}" SelectedItem="{Binding Customer}">

<!--  command that removes an item from the collection -->
<Button Grid.Column="1" Content="Remove" Command="{Binding Path=RemovePerson}"/>    

// ItemsSource of customers  
private ObservableCollection<Customer> _customers = Customer.GetSampleCustomerList();
public ObservableCollection<Customer> Customers
{
   get
   {
     return _customers;
   }
}

// selected customer from XAML SelectedItem
private Customer _customer = null;
public Customer Customer
{
  get { return _customer; }
  set
  {
    _customer = value;

    // if i don't check for null here removing a customer causes a NullReferenceException
    if ( _customer != null )
    {
      if (_customer.Factor != 0)
      {
        _customer.Factor = 0;
      }
      else
      {
        _customer.Factor = 1;
      }
    }
  }
}

// the button command ends up here to remove the selected item
public ICommand RemovePerson { get; set; }
private void OnRemovePerson(object obj)
{
  if ( _customers.Contains(_customer))
  {
    Customers.Remove(_customer);
  }
}

//项目客户来源
私有ObservableCollection_customers=Customer.GetSampleCustomerList（）；
公开收集客户
{
得到
{
退回客户；
}
}
//从XAML SelectedItem中选择的客户
私人客户_Customer=null；
公众客户
{
获取{return\u customer；}
设置
{
_顾客=价值；
//如果我在这里不检查null，删除客户会导致null引用异常
如果（_customer！=null）
{
如果（_customer.Factor！=0）
{
_顾客因素=0；
}
其他的
{
_顾客因素=1；
}
}
}
}
//按钮命令在此处结束，以删除所选项目
public ICommand RemovePerson{get；set；}
移除个人（对象obj）上的私有无效
{
如果（_customers.Contains（_customer））
{
客户。删除（_客户）；
}
}

这看起来像是可视部件或数据绑定的问题，而不是可观察的收集

---

尝试删除所有绑定，然后慢慢添加它们以查明问题并告诉我们发生了什么。

也有同样的问题。事实证明，在抛出错误点之前的某个地方有

（（DataGrid）sender）.BeginEdit（）

。该代码片段保留对datagrid绑定到的集合值的引用。因此，尝试使用

BindingCollection[index]=newValue来更改其中一个值引发NullReferenceException。我不得不删除begin_编辑。
请您添加一些负责删除Hanks Horam的代码。除了MyCollection.Remove（项目），我没有什么可以发布的。你为什么认为这可能会有所不同？在本例中，整个堆栈是直接向前的.NET。