我想创建一个跟踪所选项目的菜单，所以我使用嵌套的ListBoxes（因为Selectors are quite limited的选项。主ListBox是水平排列的，每个ListBoxItem包含一个TextBlock和一个StackPanel与另一个ListBox（这个垂直显示）显示“MenuItems”（我还需要跟踪所选项目）。像这样：
<ListBox DockPanel.Dock="Top" Grid.Column="0" ItemsSource="{Binding DashBoards}"
IsSynchronizedWithCurrentItem="True" SelectedItem="{Binding SelectedDashBoard}">
<ListBox.Template>
<ControlTemplate TargetType="{x:Type ListBox}">
<DockPanel>
<ScrollViewer x:Name="scrollviewer" HorizontalScrollBarVisibility="Hidden" CanContentScroll="False">
<StackPanel IsItemsHost="True" Orientation="Horizontal" />
</ScrollViewer>
</DockPanel>
</ControlTemplate>
</ListBox.Template>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Name}" />
<dx:DXExpander IsExpanded="{Binding IsSelected}">
<ListBox ItemsSource="{Binding Sections}"
IsSynchronizedWithCurrentItem="True" SelectedItem="{Binding SelectedSection}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Metadata.Name}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</dx:DXExpander>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
我设法将此ListBox显示在其他控件之上，因此它看起来像一个菜单。
现在有了问题......当我在水平ListBox中选择一个项目时，Expander扩展正常，但ListBox的高度增长，所以其他所有项目看起来也都展开了。
如何在不更改ListBox的高度的情况下仅扩展所选项目？
换句话说，如何让其中一个垂直ListBox溢出其父容器（又称水平ListBox）？
我想我需要重新构建一切，但我不知道如何开始。我找到了一些使用Canvas的解决方案，但在这种情况下它们似乎不起作用。
任何帮助都是受欢迎的，并且会孜孜不倦地投票; - ）
（注意：以防万一之前不清楚，我需要知道在水平ListBox中选择了哪个元素，以及在每个单独的垂直ListBox中选择了哪一个。这绑定到跟踪选择的相应ViewModel，并且水平和垂直ListBox都是动态填充的，因此无法在XAML中定义它们
答案 0 :(得分：2)
您可以将所选样式移出数据模板，这样它就不会应用于所有项目。
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style TargetType="ListViewItem">
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Height" Value="90"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<ListView>
<ListView.Items>
<sys:String>a</sys:String>
<sys:String>b</sys:String>
<sys:String>c</sys:String>
<sys:String>d</sys:String>
<sys:String>e</sys:String>
</ListView.Items>
</ListView>
</Grid>
</Window>
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ListView Height="16" VerticalAlignment="Top">
<ListView.Resources>
<Style TargetType="ListViewItem">
<Setter Property="Margin" Value="0,0,10,0"/>
</Style>
</ListView.Resources>
<ListView.Template>
<ControlTemplate TargetType="{x:Type ListBox}">
<StackPanel Background="LightGray" IsItemsHost="True" Orientation="Horizontal" />
</ControlTemplate>
</ListView.Template>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical" ClipToBounds="False">
<TextBlock Text="{Binding Header}" />
<Canvas>
<Expander IsExpanded="{Binding IsSelected, RelativeSource={RelativeSource AncestorType=ListViewItem}}">
<Expander.Style>
<Style TargetType="{x:Type Expander}">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
<Setter Property="VerticalContentAlignment" Value="Stretch"/>
<Setter Property="BorderBrush" Value="Transparent"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Expander}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="3" SnapsToDevicePixels="true">
<DockPanel>
<ContentPresenter x:Name="ExpandSite" DockPanel.Dock="Bottom" Focusable="false" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</DockPanel>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="true">
<Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
</Trigger>
<Trigger Property="ExpandDirection" Value="Right">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Right"/>
</Trigger>
<Trigger Property="ExpandDirection" Value="Up">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Top"/>
</Trigger>
<Trigger Property="ExpandDirection" Value="Left">
<Setter Property="DockPanel.Dock" TargetName="ExpandSite" Value="Left"/>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Expander.Style>
<ListView ItemsSource="{Binding Items}" IsSynchronizedWithCurrentItem="True" />
</Expander>
</Canvas>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
<ListView.Items>
<MenuItem Header="File">
<MenuItem.Items>
<MenuItem Header="Open" IsHitTestVisible="False"/>
<MenuItem Header="Exit" IsHitTestVisible="False"/>
</MenuItem.Items>
</MenuItem>
<MenuItem Header="Edit">
<MenuItem.Items>
<MenuItem Header="Cut" IsHitTestVisible="False"/>
<MenuItem Header="Copy" IsHitTestVisible="False"/>
<MenuItem Header="Paste" IsHitTestVisible="False"/>
</MenuItem.Items>
</MenuItem>
</ListView.Items>
</ListView>
</Grid>
</Window>