WPF DataGrid ItemsSource绑定问题

Question

我在WPF应用程序中有一个DataGrid,它将自己绑定到一个ObservableCollection对象,一切正常.现在,如果我在运行时修改数据网格中的单元格并删除内容,请将单元格留空.observableCollection的对应值不会被修改,它将是旧值.但是当我退出包含datagrid的窗口并重新启动窗口时,它会抛出一个XamlParseException,说:"设置属性'System.Windows.Controls.ItemsControl.ItemsSource'引发异常"

  StackTrace:
       at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
       at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
       at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
       at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
       at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
       at VO3.Start.InitializeComponent() in c:\VO\Trunk\VO3\Start.xaml:line 1
       at VO3.Start..ctor() in C:\VO\Trunk\VO3\Start.xaml.cs:line 103
  InnerException: System.InvalidOperationException
       Message='DeferRefresh' is not allowed during an AddNew or EditItem transaction.
       Source=PresentationFramework
       StackTrace:
            at System.Windows.Data.CollectionView.DeferRefresh()
            at System.Windows.Controls.ItemCollection.SetCollectionView(CollectionView view)
            at System.Windows.Controls.ItemCollection.SetItemsSource(IEnumerable value)
            at System.Windows.Controls.ItemsControl.OnItemsSourceChanged(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.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
            at System.Windows.DependencyObject.SetValue(DependencyProperty dp, Object value)
            at System.Windows.Baml2006.WpfKnownMemberInvoker.SetValue(Object instance, Object value)
            at MS.Internal.Xaml.Runtime.ClrObjectRuntime.SetValue(XamlMember member, Object obj, Object value)
            at MS.Internal.Xaml.Runtime.ClrObjectRuntime.SetValue(Object inst, XamlMember property, Object value)
       InnerException: 

只要关闭窗口时,它就不会抛出异常,数据网格中的任何单元格都不为空.我还在Window执行InitializeComponent Line之前检查了Collection,它看起来很完美,所有对象都有正确的值,没有空或空.我无法弄清楚为什么它会抛出这个异常.有任何想法吗？提前致谢.

XAML:

<DataGrid HeadersVisibility="All" RowHeight="19" AutoGenerateColumns="False" Grid.Row="1" CanUserResizeColumns="False"
                              CanUserAddRows="False" CanUserDeleteRows="False" Block.TextAlignment="Right" Grid.RowSpan="2" CanUserReorderColumns="False"
                              ItemsSource="{Binding Collection}" Width="132" HorizontalAlignment="Right" Margin="10,0,10,0" CanUserSortColumns="False"
                              IsEnabled="{Binding ElementName=CheckBox, Path=SelectedIndex, Converter={StaticResource startEnabledConverter}}">

Answer 1

DataGrid 和 DeferRefresh 似乎存在不少问题。这是两个相关 帖子：

一般建议似乎是将 DataGrid 的关联视图检查为 IEditableCollectionView （默认情况下，您的视图将是这样，因为上次我查看时 ObservableCollection 在绑定期间获取 ListCollectionView）并检查 IsAddingNew 和 IsEditingItem 以查看修改视图是否安全。此类修改将包括 DeferRefresh，它本质上是一个用于批量对视图进行修改的 Disposable。

据我所知，您遇到的问题是，当您更改 ItemsSource （这将更改或完全替换关联的绑定视图）时，DataGrid 处于事务的中间，或者视图设置为相信它是中间的。您正在清除单元格但尚未修改基础数据，这意味着它已开始编辑 (BeginEdit)，但尚未提交 (CommitEdit)，默认情况下，当您更改单元格时会发生这种情况。

当您关闭并重新打开窗口时会发生这种情况，这意味着保留了一些保留的状态，仍然认为事务正在进行中。也许它仍然使用与以前相同的 ListCollectionView，并且 IsEditingItem 仍然设置为 true？

该修复很可能确保在关闭窗口之前提交所有编辑。