WPF中Expander与ListBox(ItemsControl)嵌套中的问题

1. 当ListBox放在Expander中时，为了要实现实时更新数据的效果，这里使用了

ObservableCollection类型来作为数据源，

初始的简单例子如下：只有一个ListBox

xaml文件

 <Window x:Class="ObservableCollectionAddRemoveDemo.MainWindow"

         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

         Title="MainWindow" Height="350" Width="525">

     <Grid>

         <ListBox BorderBrush="Red" BorderThickness="2" HorizontalAlignment="Left" Height="Auto" Margin="37,32,0,0" VerticalAlignment="Top" Width="157" ItemsSource="{Binding}">

             <ListBox.ItemContainerStyle>

                 <Style TargetType="ListBoxItem" >

                     <Setter Property="Opacity" Value="0.5" />

                     <Setter Property="Opacity" Value="0.5" />

                     <Setter Property="MaxHeight" Value="75" />

                     <Setter Property="Background" Value="Green"/>

                     <Style.Triggers>

                         <Trigger Property="IsSelected" Value="True">

                             <Setter Property="Opacity" Value="1.0" />

                         </Trigger>

                     </Style.Triggers>

                 </Style>

             </ListBox.ItemContainerStyle>

         </ListBox>

         <ItemsControl HorizontalAlignment="Left" Height="auto" Margin="210,32,0,0" VerticalAlignment="Top" Width="157" ItemsSource="{Binding}">

             <ItemsControl.ItemContainerStyle>

                 <Style TargetType="ContentPresenter">

                     <Setter Property="Opacity" Value="0.5" />

                     <Setter Property="Opacity" Value="0.5" />

                     <Setter Property="MaxHeight" Value="75" />

                 </Style>

             </ItemsControl.ItemContainerStyle>

         </ItemsControl>

         <Button Content="Add" HorizontalAlignment="Left" Margin="398,65,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>

         <Button Content="Remove" HorizontalAlignment="Left" Margin="398,160,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_Remove"/>

     </Grid>

 </Window>

后台文件

 using System;

 using System.Collections.Generic;

 using System.Collections.ObjectModel;

 using System.Linq;

 using System.Text;

 using System.Threading.Tasks;

 using System.Windows;

 using System.Windows.Controls;

 using System.Windows.Data;

 using System.Windows.Documents;

 using System.Windows.Input;

 using System.Windows.Media;

 using System.Windows.Media.Imaging;

 using System.Windows.Navigation;

 using System.Windows.Shapes;

 namespace ObservableCollectionAddRemoveDemo

 {

     /// <summary>

     /// Interaction logic for MainWindow.xaml

     /// </summary>

     public partial class MainWindow : Window

     {

         public ObservableCollection<String> list;

         //public List<String> list;

         public MainWindow()

         {

             InitializeComponent();

             list = new ObservableCollection<string>() { "asda","12asdas","a22321","asda112323","xcvcvcxv","aasda","","asdasdasd"};

             this.DataContext = list;

         }

         private void Button_Click(object sender, RoutedEventArgs e)

         {

             int addNumber = new Random().Next();

             list.Add(addNumber.ToString());

         }

         private void Button_Click_Remove(object sender, RoutedEventArgs e)

         {

             if (list.Count > )

                 list.RemoveAt();

         }

     }

 }

发现代码实现的很顺畅，无论是增删都能实时响应到界面中

2. 但当在ListBox外面套一个Expander时，问题就出现了，如下图：

在删除数据时，内容明显变少了，但属于删掉内容的位置确仍然保留在界面上！！！

解决的办法是：在Expander的 ContentPresenter外面套一个StackPanel，如下：

  <StackPanel>

          <ContentPresenter x:Name="ExpanderContent" ContentSource="Content"/>

 </StackPanel>

===========================================

当将Expander放在ListBox中时也有可能会出现类似的问题：https://www.dotblogs.com.tw/ouch1978/archive/2011/03/11/wpf-expander-in-listbox.aspx

巴特西

WPF中Expander与ListBox(ItemsControl)嵌套中的问题

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