无法访问 ColumnHeader 的文本（模板）
在 DataGridColumnHeader 的模板中，我创建了一个标签，如果多重绑定符合规则，则该标签只应在标题文本旁边显示数值。
我已在 UserControl 上成功创建了此代码，并且其按预期工作。
但现在在 Windows Control 上，这不再起作用，我完全无言以对。
多重绑定中的
我收到以下错误消息：
System.Windows.Data 警告：40：BindingExpression 路径错误：“文本” 在“对象”“iReportViewModel”上找不到属性 （哈希码=36680867）'。绑定表达式：路径=文本； DataItem='iReportViewModel'（哈希码=36680867）；目标元素是 '标签'（名称='ColumnHeaderSortingNumber'）；目标属性是 “内容”（类型“对象”）
但这如何在我的其他用户控件上使用精确的副本和内容？粘贴代码？ 为什么要查看 ViewModel？我期望访问 ViewModel，如果其定义如下： Path="DataContext.Text" 就像第二行一样。这应该访问同一标题中的文本（标题）。
任何帮助我的想法将不胜感激，
<Style x:Key="DatagridColumnHeaderCustomTemplateStyle" TargetType="{x:Type DataGridColumnHeader}">
...
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridColumnHeader}">
<Grid>
<Grid.ColumnDefinitions>
...
</Grid.RowDefinitions>
<theme:DataGridHeaderBorder>
...
</theme:DataGridHeaderBorder>
<Label FontSize="8" FontWeight="Bold" Background="Transparent" Style="{StaticResource ColumnHeaderSortingLabel}" x:Name="ColumnHeaderSortingNumber" Panel.ZIndex="1000" Visibility="Collapsed" Grid.Column="1" Grid.Row="1" Grid.ColumnSpan="2" Margin="0" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" >
<Label.Content>
<MultiBinding Converter="{StaticResource ColumnHeaderDictionaryConv}" ConverterParameter="LookupSecond" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
<Binding Path="Text" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type DataGridCellsPanel}}" Path="DataContext.SortCollectionHeader" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/>
<Binding ... />
</MultiBinding>
</Label.Content>
</Label>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
WIthin the DataGridColumnHeader's template I have created a label that should only show a numeric value next to the header's text, if the multibinding matches the rules.
I have successfully created this code on a UserControl and its working as expected.
But now on a Windows Control, this doesn't work any longer and I am completely speechless why that is.
The line <Binding Path="Text" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/> within Multibinding is meant to bind to the Text property of the actual header. But this binding doesn't seem to work.
I get the following error message:
System.Windows.Data Warning: 40 : BindingExpression path error: 'Text'
property not found on 'object' ''iReportViewModel'
(HashCode=36680867)'. BindingExpression:Path=Text;
DataItem='iReportViewModel' (HashCode=36680867); target element is
'Label' (Name='ColumnHeaderSortingNumber'); target property is
'Content' (type 'Object')
But how comes this works on my other usercontrol with teh exact copy & pasted code?
Why is it looking at the ViewModel? I was expecting to access the ViewModel if its defined like this: Path="DataContext.Text" like the second row. This should have accessed the Text (title) within the same header.
Any idea to help me out would be highly appreciated,
<Style x:Key="DatagridColumnHeaderCustomTemplateStyle" TargetType="{x:Type DataGridColumnHeader}">
...
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridColumnHeader}">
<Grid>
<Grid.ColumnDefinitions>
...
</Grid.RowDefinitions>
<theme:DataGridHeaderBorder>
...
</theme:DataGridHeaderBorder>
<Label FontSize="8" FontWeight="Bold" Background="Transparent" Style="{StaticResource ColumnHeaderSortingLabel}" x:Name="ColumnHeaderSortingNumber" Panel.ZIndex="1000" Visibility="Collapsed" Grid.Column="1" Grid.Row="1" Grid.ColumnSpan="2" Margin="0" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" >
<Label.Content>
<MultiBinding Converter="{StaticResource ColumnHeaderDictionaryConv}" ConverterParameter="LookupSecond" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
<Binding Path="Text" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/>
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type DataGridCellsPanel}}" Path="DataContext.SortCollectionHeader" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"/>
<Binding ... />
</MultiBinding>
</Label.Content>
</Label>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
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您可能应该已经知道这一点，如果
Binding中未指定源，它将在DataContext中查找Path中指定的属性。来源有：ElementName、Source&RelativeSource，这就是为什么您在第二个绑定中需要DataContext.X的原因，否则会在源上查找属性。如果要绑定到拥有该属性的控件上的属性，请添加
RelativeSource="{RelativeSource Self}"。如果您想绑定到模板化父级上的属性，您可以使用TemplateBinding或也使用RelativeSource和TemplatedParent而不是自我。You probably should know this already, if no source is specified in a
Bindingit will be looking for the property specified inPathin theDataContext. Sources are:ElementName,Source&RelativeSource, this is why you needDataContext.Xin the second binding as that would be looking for the property on the source otherwise.If you want to bind to a property on the control that owns the property you are bindng add
RelativeSource="{RelativeSource Self}". If you want to bind to a property on the templated parent you can either use aTemplateBindingor also useRelativeSourcewithTemplatedParentinstead ofSelf.