How to collapse all Group Expander in ListView? - wpf

Question

I have a ListView with a GroupStyle on it. And in the style i have an Expander. I want to use a ContextMenu in the ListView to collapse and expand all groups with one click and i want to expand every single group by clicking on the expander. How can i get the Groups and then expand this programmatically?
<Style x:Key="PropertyGroupStyle" TargetType="{x:Type GroupItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Expander Header="{Binding Name}" IsExpanded="True">
<ItemsPresenter />
</Expander>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ListView Name="PropertyChangeList"
IsSynchronizedWithCurrentItem="True" Height="Auto"
ItemsSource="{Binding}"
>
<ListView.GroupStyle>
<GroupStyle ContainerStyle="{StaticResource PropertyGroupStyle}"/>
</ListView.GroupStyle>
<ListView.ContextMenu>
<ContextMenu>
<MenuItem Name="menuItemPropertyExpanderCollapse"
Header="{Binding Path=labelCollapse, FallbackValue='Collapse'}"
Click="menuItemPropertyExpanderCollapse_Click"
/>
<MenuItem Name="menuItemPropertyExpanderExpand"
Header="{Binding Path=labelExpand, FallbackValue='Expand'}"
/>
</ContextMenu>
</ListView.ContextMenu>
<ListView.View>
<GridView AllowsColumnReorder="False" >
<GridViewColumn Header="Date Occured"
Width="20"
DisplayMemberBinding="{Binding DateOccured}" />
<GridViewColumn Header="PropertyName"
Width="Auto"
DisplayMemberBinding="{Binding PropertyName}"/>
</GridView>
</ListView.View>
</ListView>
ICollectionView PropertyListview = CollectionViewSource.GetDefaultView(hPropList);
PropertyListview.GroupDescriptions.Add(new PropertyGroupDescription("PropertyName"));
PropertyListview.SortDescriptions.Add(new SortDescription("PropertyName", ListSortDirection.Ascending));
PropertyListview.SortDescriptions.Add(new SortDescription("DateOccurred", ListSortDirection.Ascending));
PropertyChangeList.ItemsSource = PropertyListview;
Has anybody an sample code to do the collapse and expand all groups with an ContextMenu? i dont find anything out there.

Answer 1

You could bind the IsExpanded property to the Tag property of the ListView:
<Style x:Key="PropertyGroupStyle" TargetType="{x:Type GroupItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Expander Header="{Binding Name}"
IsExpanded="{Binding Tag, RelativeSource={RelativeSource AncestorType=ListView}, TargetNullValue=true, FallbackValue=true}">
<ItemsPresenter />
</Expander>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
...and set the Tag property in the event handlers:
private void menuItemPropertyExpanderCollapse_Click(object sender, RoutedEventArgs e)
{
PropertyChangeList.Tag = false;
}
you answered the question right, but i forget to write more details. Yes now i can expand and collapse all groups but i cant expand anymore a single group. it is an all or nothing thing. My question missed some important details :-( I updated my question text.
Change the AncestorType of the binding to GroupItem and set the Tag property of each GroupItem by iterating through them in the visual tree:
private void menuItemPropertyExpanderCollapse_Click(object sender, RoutedEventArgs e)
{
foreach (GroupItem gi in FindVisualChildren<GroupItem>(PropertyChangeList))
gi.Tag = false;
}
private static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
if (depObj != null)
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
if (child != null && child is T)
{
yield return (T)child;
}
foreach (T childOfChild in FindVisualChildren<T>(child))
{
yield return childOfChild;
}
}
}
}
XAML:
<Expander Header="{Binding Name}"
IsExpanded="{Binding Tag, RelativeSource={RelativeSource AncestorType=GroupItem}, TargetNullValue=true, FallbackValue=true}">
<ItemsPresenter />
</Expander>