ScrollViewer in Expander

问题

I have a ListBox with Expanders which in turn contains a ListBox. I would like to have both the ListBox with Expanders (listBox1) and the ListBox inside each Expander (listBox2) to have scroll functionality, but I cannot get the innermost scrolling to work (i.e. scrollViewer1 in my XAML).

How can I get both scrollbars to work?

<ScrollViewer x:Name="scrollViewer1">
   <ListBox x:Name="listBox1" ItemsSource="{Binding Data}">
       <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel>
                    <Expander>
                        <Expander.Header>
                            <TextBlock Text="{Binding Name}">
                            </TextBlock>
                        </Expander.Header>
                        <ScrollViewer x:Name="scrollViewer2">
                            <ListBox x:Name="listBox2" ItemsSource="{Binding Numbers}">
                                <ListBox.ItemTemplate>
                                    <DataTemplate>
                                        <StackPanel>
                                            <Grid>
                                                <TextBlock Grid.Column="0" Text="{Binding}"/>
                                            </Grid>
                                        </StackPanel>
                                    </DataTemplate>
                                </ListBox.ItemTemplate>
                            </ListBox>
                        </ScrollViewer>
                    </Expander>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
   </ListBox>

回答1:

First of all, you d'ont need the scrollviewer tags: The listbox handles the scrolling by itself. To control the visibilty of the listbox scrollbar you ca use the ScrollViewer.HorizontalScrollBarVisibility and ScrollViewer.VerticalScrollBarVisibility.

Second, the vertical scrollbar of the inner listbox does not appear because without height limitations the listbox will expand to display all the items.

Here is a working code wich shows both scroll bar of parent and inner listbox :

<Window x:Class="StackOverflow.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 x:Name="listBox1" ItemsSource="{Binding Clients}">
        <ListBox.ItemTemplate>
            <DataTemplate>

                <Expander>
                    <Expander.Header>
                        <TextBlock Text="{Binding Name}">
                        </TextBlock>
                    </Expander.Header>

                    <ListBox x:Name="listBox2" ItemsSource="{Binding Children}" MaxHeight="150">
                        <ListBox.ItemTemplate>
                            <DataTemplate>
                                <StackPanel>
                                    <Grid>
                                        <TextBlock Grid.Column="0" Text="{Binding Name}"/>
                                    </Grid>
                                </StackPanel>
                            </DataTemplate>
                        </ListBox.ItemTemplate>
                    </ListBox>

                </Expander>

            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>
</Window>

To reproduce your problem, just remove the MaxHeight on the second listbox.

来源：https://stackoverflow.com/questions/32648912/scrollviewer-in-expander