ListBox展开所选项目

我有以下代码片段（复制并粘贴到kaxaml，xamlpad等尝试它），折叠除了所选项目以外的所有项目 . 但是，当鼠标没有超过 ListBox 时，我想恢复到所有可见的状态，而我无法让它无法完成后面的代码 . 我正在使用 IsMouseOver ListBox属性在 ListBox 上设置所选项属性以尝试触发更新但没有运气 . 有任何想法吗？

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
 <Grid>
      <ListBox
           Name="lb"
           Width="100"
           Height="100"
           Background="Red"
           SelectionMode="Single">
           <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                     <UniformGrid Columns="1"/>
                </ItemsPanelTemplate>
           </ListBox.ItemsPanel>
           <ListBoxItem Background="AliceBlue">Item 1    
           </ListBoxItem>
           <ListBoxItem Background="Aquamarine">Item 
           </ListBoxItem>
           <ListBoxItem Background="Azure">Item 
           </ListBoxItem>
           <ListBox.ItemContainerStyle>
                <Style TargetType="{x:Type ListBoxItem}">
                     <Setter Property="Visibility" Value="Visible"/>
                     <Style.Triggers>
                          <MultiDataTrigger>
                               <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsSelected}" Value="False"/>
                                    <Condition Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBox}},Path=SelectedItems.Count}" Value="1"/>
                               </MultiDataTrigger.Conditions>
                               <MultiDataTrigger.EnterActions>
                                    <BeginStoryboard>
                                         <Storyboard Duration="0:0:1">
                                              <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility">
                                                   <DiscreteObjectKeyFrame KeyTime="0:0:1" Value="{x:Static Visibility.Collapsed}"/>
                                              </ObjectAnimationUsingKeyFrames>
                                              <DoubleAnimation Duration="0:0:1" Storyboard.TargetProperty="Opacity" To="0"/>
                                         </Storyboard>
                                    </BeginStoryboard>
                               </MultiDataTrigger.EnterActions>
                          </MultiDataTrigger>
                          <MultiDataTrigger>
                               <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsSelected}" Value="True"/>
                                    <Condition Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBox}},Path=SelectedItems.Count}" Value="1"/>
                               </MultiDataTrigger.Conditions>
                               <MultiDataTrigger.EnterActions>
                                    <BeginStoryboard>
                                         <Storyboard Duration="0:0:0">
                                              <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility">
                                                   <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="{x:Static Visibility.Visible}"/>
                                              </ObjectAnimationUsingKeyFrames>
                                              <DoubleAnimation Duration="0:0:0" Storyboard.TargetProperty="Opacity" To="1"/>
                                         </Storyboard>
                                    </BeginStoryboard>
                               </MultiDataTrigger.EnterActions>
                          </MultiDataTrigger>
                     </Style.Triggers>
                </Style>
           </ListBox.ItemContainerStyle>
           <ListBox.Style>
                <Style>
                     <Style.Triggers>
                          <Trigger Property="ListBox.IsMouseOver" Value="False">
                               <Setter Property="ListBox.SelectedItem" Value="{x:Null}"/>
                               <Setter Property="ListBoxItem.IsSelected" Value="False"/>
                               <Setter Property="ListBox.SelectedIndex" Value="-1"/>
                          </Trigger>
                          <EventTrigger RoutedEvent="Mouse.MouseLeave">
                               <BeginStoryboard>
                                    <Storyboard>
                                         <Int32Animation Duration="0:0:0" Storyboard.TargetProperty="SelectedIndex" To="-1"/>
                                    </Storyboard>
                               </BeginStoryboard>
                          </EventTrigger>
                     </Style.Triggers>
                </Style>
           </ListBox.Style>
      </ListBox>
 </Grid>
</Page>