.net - VirtualizingStackPanel 未正确处理折叠的项目

Question

我在 wpf 中有一个 ListView 用于显示字段列表；基于属性值，某些字段可以在运行时折叠。它工作正常，除了 ListVIew 不会折叠为 ListViewItem 保留的空间，这些空间在运行时被折叠了。

我能够在 Snoop 中看到额外的 ListViewItems(具有折叠的可见性)，ListView 也会向上移动项目，但它不会调整其高度以删除空白空间!

我可以肯定地说，这是由于 VirtualizedStackPanel 而发生的，因为将 ItemsPanel 更改为 StackPanel 可以解决问题。这是相关的 ListView XAML:

<ListView
    x:Class="Wizards.FieldBinderModelListView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Margin="0"
    VerticalAlignment="Top"
    HorizontalContentAlignment="Stretch"
    VerticalContentAlignment="Top"
    Background="White"
    BorderThickness="0"
    Grid.IsSharedSizeScope="True"
    KeyboardNavigation.DirectionalNavigation="Continue"
    Padding="1"
    ScrollViewer.HorizontalScrollBarVisibility="Hidden"
    ScrollViewer.VerticalScrollBarVisibility="Hidden"
    SelectionChanged="ListViewSelectionChanged"
    SelectionMode="Single">
    <ListView.ItemsPanel>
       <ItemsPanelTemplate>
        <!--Works fine with StackPanel but not with VirtualizingStackPanel
          Explicitly added this PanelTemplate to show that it works with            
          StackPanel;ListView uses VirtualizingStackPanel as default panel 
          and causes same problem-->              
        <!--<StackPanel Orientation="Vertical" VerticalAlignment="Top"/>-->
          <VirtualizingStackPanel Orientation="Vertical" 
               VerticalAlignment="Top"/>
       </ItemsPanelTemplate>
    </ListView.ItemsPanel>
    <ListView.ItemContainerStyle>
      <Style TargetType="{x:Type ListViewItem}">
        <Style.Triggers>
            <Trigger Property="IsSelected" Value="True">
                <Setter Property="Foreground" Value="Black" />
            </Trigger>
            <DataTrigger Binding="{Binding Status}"
                         Value="{x:Static local:Status.NotExisting}">
                <!--Hide the fields which are in NotExisting state; 
                  Need a trigger here as Status can be different -->
                <Setter Property="Visibility" Value="Collapsed" />
            </DataTrigger>
        </Style.Triggers>
      </Style>
  </ListView.ItemContainerStyle>
  <ListView.ItemTemplate>
    <DataTemplate DataType="{x:Type View:FieldViewModel}">
       <local:FieldEditor
          Margin="0,2,0,0"
          HorizontalAlignment="Stretch"
          VerticalAlignment="Top"
          HorizontalContentAlignment="Stretch"
          VerticalContentAlignment="Top"
          Padding="0">
          <!--<local:FieldEditor.Style>
              <Style TargetType="{x:Type local:FieldEditor}">
                <Style.Triggers>
                  <DataTrigger
                    Binding="{Binding Status}"
                    Value="{x:Static local:Status.NotExisting}">
                      <Setter Property="Visibility" Value="Collapsed" />
                  </DataTrigger>
                </Style.Triggers>
              </Style>
            </local:FieldEditor.Style>-->
        </local:FieldEditor>
    </DataTemplate>
  </ListView.ItemTemplate>
</ListView>

这是 VirtualizingStackPanel 中的错误吗？还有其他人遇到过类似的问题吗？有什么解决方法吗？

---

更新:

在连接时将此错误报告给 MS - https://connect.microsoft.com/VisualStudio/feedback/details/734113/virtualizingstackpanel-not-handling-collapsed-items-correctly

Answer 1

我设法重现了您的问题。它看起来确实像 VirtualizingStackPanel 中的一个错误。一种解决方法是将隐藏项的高度设置为零而不是折叠它们:

<DataTrigger Binding="{Binding Status}" Value="False">
    <Setter Property="Height" Value="0" />
    <Setter Property="IsEnabled" Value="False"/>
    <!--<Setter Property="Visibility" Value="Collapsed" />-->
</DataTrigger>