什么是数据绑定环境中的缓存评估者?

时间:2013-01-24 15:27:30

标签: wpf data-binding

我得到了绑定的跟踪信息:

    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 -> SourceSource -> Target 除此之外,我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。我不知道这个功能被破坏的原因是什么,因为VS2012以红色打印警告106我觉得问题就在这个消息附近。

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>

1 个答案:

答案 0 :(得分:1)

我真的不知道为什么,但这条街头魔法有帮助!

是:

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

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'

绑定现在可以两种方式工作 我认为DataGridCell的DataContext继承和样式应用程序存在一个问题 确切地说,这个顺序在这里很重要,我想 如果应用Style,则首先Data Binding尝试获取尚未继承的DataContext,并以某种方式中断绑定而不会更新 我会尝试重现这个错误,如果我设法做到这一点,我会写信给MS Connect。