Question

我将ListView声明为：

<ListView x:Name="Tree"
      ItemsSource="{Binding ElementName=This, Path=Some.Path.Values}"
      AlternationCount="2"
      ScrollViewer.CanContentScroll="False">

和定义为

的样式

<UserControl.Resources>
<Style TargetType="ListViewItem">
    <Style.Resources>
        <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="SteelBlue"/>
        <SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="Gray"/>
    </Style.Resources>
    <Style.Triggers>
        <Trigger Property="ItemsControl.AlternationIndex" Value="0">
            <Setter Property="Background" Value="White" />
        </Trigger>
        <Trigger Property="ItemsControl.AlternationIndex" Value="1">
            <Setter Property="Background" Value="GhostWhite" />
        </Trigger>
    </Style.Triggers>
    <Setter Property="HorizontalContentAlignment" Value="Stretch" />
    <Setter Property="VerticalContentAlignment" Value="Top" />
    <EventSetter Event="Loaded" Handler="ContinueLoading" />
</Style>

这种组合产生了原始的期望行为，即交替背景高光的行为。新的期望行为是根据给定ListView项的属性值更改该背景颜色;因此Style.Triggers已更改为

<Style.Triggers>
    <Trigger Property="ItemsControl.AlternationIndex" Value="0">
        <Setter Property="Background" Value="White" />
    </Trigger>
    <Trigger Property="ItemsControl.AlternationIndex" Value="1">
        <Setter Property="Background" Value="GhostWhite" />
    </Trigger>
    <MultiDataTrigger>
        <MultiDataTrigger.Conditions>
            <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}}, Path=(ItemsControl.AlternationIndex)}" Value="0"/>
            <Condition Binding="{Binding Converter={x:Static controls:Converters.ObjectType}}" Value="{x:Type client:DocumentEntryTypeA}" />
        </MultiDataTrigger.Conditions>
        <Setter Property="Background" Value="{Binding Converter={x:Static controls:Converters.LightColor}, UpdateSourceTrigger=PropertyChanged, Path=Status}" />
    </MultiDataTrigger>
    <MultiDataTrigger>
        <MultiDataTrigger.Conditions>
            <Condition Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}}, Path=(ItemsControl.AlternationIndex)}" Value="1"/>
            <Condition Binding="{Binding Converter={x:Static controls:Converters.ObjectType}}" Value="{x:Type client:DocumentEntryTypeA}" />
        </MultiDataTrigger.Conditions>
        <Setter Property="Background" Value="{Binding Converter={x:Static controls:Converters.DarkColor}, UpdateSourceTrigger=PropertyChanged, Path=Status}" />
    </MultiDataTrigger>
</Style.Triggers>
</UserControl.Resources>

ObjectType转换器检查元素是否为给定类; LightColor和DarkColor转换器会根据Status属性的值生成所选的背景值。

这段代码的问题在于我使用的绑定似乎总是产生AlternationIndex值为'0'，即Converter LightColor用于每个条目。除了上面的代码之外，我还尝试了以下具有相同结果的绑定：

<Condition Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ItemsControl}, Path=AlternationIndex}" Value="0"/>
<Condition Binding="{Binding RelativeSource={RelativeSource AncestorType={x:Type ListView}}, Path=(ItemsControl.AlternationIndex)}" Value="0"/>

根据我见过的例子，大多数解决方案都没有将风格与对象分开;在我的情况下，样式在UserControl.Resources内单独定义。但是，由于使用Trigger工作正常，我不确定为什么DataTrigger没有，或者需要什么来使它工作。

Answer 1

MultiDataTrigger中的第一个条件是找到最新的ContentPresenter，并尝试绑定到ContentPresenter.ItemsControl.AlternationIndex，而ItemsControl.AlternationIndex不是ContentPresenter的有效属性}。

尝试将其更改为RelativeSource={RelativeSource Self}，以便绑定到当前对象的ItemsControl.AlternationIndex

带有AlternationIndex的MultiDataTrigger

1 个答案: