什么是数据绑定上下文中的缓存容器

Question

我得到绑定的跟踪信息：

    System.Windows.Data Warning: 55 : Created BindingExpression (hash=45919010) for Binding (hash=4523055)
    System.Windows.Data Warning: 57 :   Path: 'IsEnvelopeFocused'
    System.Windows.Data Warning: 59 : BindingExpression (hash=45919010): Default mode resolved to TwoWay
    System.Windows.Data Warning: 60 : BindingExpression (hash=45919010): Default update trigger resolved to PropertyChanged
    System.Windows.Data Warning: 61 : BindingExpression (hash=45919010): Attach to System.Windows.Controls.DataGridCell.IsFocused (hash=42777048)
    System.Windows.Data Warning: 66 : BindingExpression (hash=45919010): Resolving source 
    System.Windows.Data Warning: 69 : BindingExpression (hash=45919010): Found data context element: DataGridCell (hash=42777048) (OK)
    System.Windows.Data Warning: 77 : BindingExpression (hash=45919010): Activate with root item VulnerEnvelope (hash=53089570)
    System.Windows.Data Warning: 106 : BindingExpression (hash=45919010):   At level 0 using cached 
accessor for VulnerEnvelope.IsEnvelopeFocused: RuntimePropertyInfo(IsEnvelopeFocused)
    System.Windows.Data Warning: 103 : BindingExpression (hash=45919010): Replace item at level 0 with VulnerEnvelope (hash=53089570), using accessor RuntimePropertyInfo(IsEnvelopeFocused)
    System.Windows.Data Warning: 100 : BindingExpression (hash=45919010): GetValue at level 0 from VulnerEnvelope (hash=53089570) using RuntimePropertyInfo(IsEnvelopeFocused): 'False'
    System.Windows.Data Warning: 79 : BindingExpression (hash=45919010): TransferValue - got raw value 'False'

我还使用转换器输出数据流：Target -> Source和Source -> Target。
除此之外，我还会在每次更改时输出附加属性的绑定信息。
绑定保持活动状态，但源和目标不同步。我不知道此功能损坏的原因是什么，并且由于VS2012以红色打印警告106，我认为问题在此消息附近的某个地方。

这是绑定：

<DataGridTemplateColumn Width="*" CanUserResize="True" CanUserSort="True" Header=" Title "
                                                SortMemberPath=".">
  <DataGridTemplateColumn.CellStyle>
    <Style TargetType="DataGridCell">
      <Setter Property="Helpers:FocusHelper.IsFocused" Value="{Binding IsEnvelopeFocused, Converter={StaticResource bdc}, PresentationTraceSources.TraceLevel=High}"/>
    </Style>
  </DataGridTemplateColumn.CellStyle>
  <DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
      <TextBlock Name="txtTitle" VerticalAlignment="Center">
        <TextBlock.Text>
          <MultiBinding Converter="{StaticResource TitleConverter}" UpdateSourceTrigger="PropertyChanged">
            <Binding Path="." />
            <Binding Path="DataContext.Language" RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=UserControl}" />
          </MultiBinding>
        </TextBlock.Text>
      </TextBlock>
    </DataTemplate>
  </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

Answer 1

我真的不知道为什么，但这个街头魔法有帮助！

它是：

<Setter Property="Helpers:FocusHelper.IsFocused" Value="{Binding IsEnvelopeFocused,
                                Converter={StaticResource bdc}, 
                                PresentationTraceSources.TraceLevel=High}"/>

它变成了：

<Setter Property="Helpers:FocusHelper.IsFocused" Value="{Binding DataContext.IsEnvelopeFocused, 
                                Converter={StaticResource bdc}, 
                                PresentationTraceSources.TraceLevel=High, 
                                RelativeSource={RelativeSource Self}}"/>

数据绑定跟踪输出已更改：

System.Windows.Data Warning: 55 : Created BindingExpression (hash=52742621) for Binding (hash=33023833)
System.Windows.Data Warning: 57 :   Path: 'DataContext.IsEnvelopeFocused'
System.Windows.Data Warning: 59 : BindingExpression (hash=52742621): Default mode resolved to TwoWay
System.Windows.Data Warning: 60 : BindingExpression (hash=52742621): Default update trigger resolved to PropertyChanged
System.Windows.Data Warning: 61 : BindingExpression (hash=52742621): Attach to System.Windows.Controls.DataGridCell.IsFocused (hash=34022436)
System.Windows.Data Warning: 66 : BindingExpression (hash=52742621): Resolving source 
System.Windows.Data Warning: 69 : BindingExpression (hash=52742621): Found data context element: <null> (OK)
System.Windows.Data Warning: 71 :   RelativeSource.Self found DataGridCell (hash=34022436)
System.Windows.Data Warning: 77 : BindingExpression (hash=52742621): Activate with root item DataGridCell (hash=34022436)
System.Windows.Data Warning: 106 : BindingExpression (hash=52742621):   At level 0 using cached accessor for DataGridCell.DataContext: DependencyProperty(DataContext)
System.Windows.Data Warning: 103 : BindingExpression (hash=52742621): Replace item at level 0 with DataGridCell (hash=34022436), using accessor DependencyProperty(DataContext)
System.Windows.Data Warning: 100 : BindingExpression (hash=52742621): GetValue at level 0 from DataGridCell (hash=34022436) using DependencyProperty(DataContext): VulnerEnvelope (hash=14963839)
System.Windows.Data Warning: 106 : BindingExpression (hash=52742621):   At level 1 using cached accessor for VulnerEnvelope.IsEnvelopeFocused: RuntimePropertyInfo(IsEnvelopeFocused)
System.Windows.Data Warning: 103 : BindingExpression (hash=52742621): Replace item at level 1 with VulnerEnvelope (hash=14963839), using accessor RuntimePropertyInfo(IsEnvelopeFocused)
System.Windows.Data Warning: 100 : BindingExpression (hash=52742621): GetValue at level 1 from VulnerEnvelope (hash=14963839) using RuntimePropertyInfo(IsEnvelopeFocused): 'False'
System.Windows.Data Warning: 79 : BindingExpression (hash=52742621): TransferValue - got raw value 'False'
System.Windows.Data Warning: 81 : BindingExpression (hash=52742621): TransferValue - user's converter produced 'False'
System.Windows.Data Warning: 88 : BindingExpression (hash=52742621): TransferValue - using final value 'False'

绑定现在以两种方式工作。
我认为DataGridCell的DataContext继承和样式应用有一个兄弟。
确切地说，我想这里的顺序很重要。
如果首先应用样式，则数据绑定会尝试获取尚未继承的 DataContext，并且以某种方式破坏绑定，导致没有更新。
我将尝试重现此错误，如果我设法做到这一点，我将写信给MS Connect。