ComboBoxEdit.GroupStyle Property

Gets a collection of GroupStyle objects that define the appearance of each group level.

Namespace: DevExpress.Xpf.Editors

Assembly: DevExpress.Xpf.Core.v24.1.dll

NuGet Package: DevExpress.Wpf.Core

Declaration

C#

public ObservableCollection<GroupStyle> GroupStyle { get; }

VB.NET

Public ReadOnly Property GroupStyle As ObservableCollection(Of GroupStyle)

Property Value

Type	Description
ObservableCollection<GroupStyle>	One or more GroupStyle objects.

Remarks

DevExpress WPF ComboBoxEdit, LookUpEdit, and ListBoxEdit controls include support for ICollectionView – allowing you to manipulate the current record and define rules for filtering, sorting, and grouping.

By default, if a grouping rule is defined in the ICollectionView, editors display the plain list in which items are sorted to meet data grouping. Use the GroupStyle property to visually enhance the presentation of grouped items. For instance, you can display expandable groups (see the image below):

XAML

<Grid.Resources>
    <DataTemplate x:Key="headerTemplate">
        <TextBlock Text="{Binding}" FontWeight="Bold" TextDecorations="Underline"/>
    </DataTemplate>
</Grid.Resources>
<!-- ... -->
<dxe:ComboBoxEdit ItemsSource="{Binding GroupedCities}" 
                  AllowCollectionView="True" 
                  DisplayMember="CityName">
    <dxe:ComboBoxEdit.GroupStyle>
        <GroupStyle HidesIfEmpty="True">
            <GroupStyle.ContainerStyle>
                <Style TargetType="{x:Type GroupItem}">
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate>
                                <Expander Header="{Binding Path=Name}" 
                                          HeaderTemplate="{StaticResource headerTemplate}" 
                                          IsExpanded="True"
                                          HorizontalContentAlignment="Stretch" 
                                          Margin="3,3,3,0">
                                    <ItemsPresenter />
                                </Expander>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </GroupStyle.ContainerStyle>
        </GroupStyle>
    </dxe:ComboBoxEdit.GroupStyle>
</dxe:ComboBoxEdit>

Note

When grouping is used, the ComboBoxEdit control scrolls items per group by default. To change this behavior, set the VirtualizingPanel.IsVirtualizingWhenGrouping attached property to true.

Xaml

<dxe:ComboBoxEdit VirtualizingPanel.IsVirtualizingWhenGrouping="True">
   ...
</dxe:ComboBoxEdit>