带有 XmlDataProvider 和 ContentControl 的 WPF 网格？

Question

DataTemplate x:Key="CellTemplate" 未到达网格 ContentControl 的 DataContext 出了什么问题？

<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="WpfApplication1.Page1">
    <Page.Resources>
        <XmlDataProvider x:Key="xml">
            <x:XData>
                <root xmlns="">
                    <foo a="one" />
                    <foo a="two" />
                    <foo a="three" />
                    <foo a="four" />
                </root>
            </x:XData>
        </XmlDataProvider>
    </Page.Resources>
    <Grid DataContext="{Binding Mode=Default, Source={StaticResource xml}}">
        <Grid.Resources>
            <DataTemplate x:Key="CellTemplate">
                <TextBlock Foreground="AntiqueWhite"
                           Text="{Binding Mode=Default, XPath=.}" />
                <DataTemplate.Triggers>
                    <DataTrigger Binding="{Binding XPath=.}" Value="three">
                        <Setter Property="TextBlock.FontWeight" Value="Bold" />
                    </DataTrigger>
                </DataTemplate.Triggers>
            </DataTemplate>
        </Grid.Resources>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <ContentControl Grid.Row="0" 
            ContentTemplate="{StaticResource CellTemplate}"
            DataContext="{Binding Mode=Default, XPath=/root/foo[1]/@a}" />    
        <ContentControl Grid.Row="1"
            ContentTemplate="{StaticResource CellTemplate}"
            DataContext="{Binding Mode=Default, XPath=/root/foo[2]/@a}" />    
        <ContentControl Grid.Row="2" 
            ContentTemplate="{StaticResource CellTemplate}"
            DataContext="{Binding Mode=Default, XPath=/root/foo[3]/@a}" />
        <ContentControl Grid.Row="3" 
            ContentTemplate="{StaticResource CellTemplate}"
            DataContext="{Binding Mode=Default, XPath=/root/foo[4]/@a}" />
    </Grid>
</Page>

Answer 1

弄清楚了，这很令人困惑，但是数据模板内的数据上下文设置为内容控件的内容，而不是其数据上下文。设置其内容，而不是设置每个内容控件的数据上下文。

示例：

<ContentControl Grid.Row="1"
    ContentTemplate="{StaticResource CellTemplate}"
    Content="{Binding Mode=Default, XPath=/root/foo[1]/@a}" />

或者，或者：

<ContentControl Grid.Row="0" 
    ContentTemplate="{StaticResource CellTemplate}"
    DataContext="{Binding Mode=Default, XPath=/root/foo[1]/@a}" 
    Content="{Binding}" />