#984 – Grouping Items in a ListBox with a CollectionViewSource

Similar to how you can use a CollectionViewSource to sort a collection of items in a ListBox, you can also use the CollectionViewSource to group the items, based on a property on the underlying object that you’re binding to.

Assume that you have an Actor object that has a LastName property and a DecadeBorn property that indicates what decade an actor was born in.  You can group the actors by decade and then sort within each decade by last name as shown below.

    <Window.Resources>
        <CollectionViewSource x:Key="cvsActors" Source="{Binding ActorList}" >
            <CollectionViewSource.SortDescriptions>
                <scm:SortDescription PropertyName="DecadeBorn" />
                <scm:SortDescription PropertyName="LastName" />
            </CollectionViewSource.SortDescriptions>
            <CollectionViewSource.GroupDescriptions>
                <data:PropertyGroupDescription  PropertyName="DecadeBorn"/>
            </CollectionViewSource.GroupDescriptions>
        </CollectionViewSource>
    </Window.Resources>

    <StackPanel>
        <ListBox Name="lbActors" Margin="15" Width="200" Height="240"
                 ItemsSource="{Binding Source={StaticResource cvsActors}}">
            <ListBox.GroupStyle>
                <GroupStyle/>
            </ListBox.GroupStyle>
        </ListBox>
    </StackPanel>

The empty GroupStyle element will cause the group to be rendered using a string representation of the DecadeBorn property.

We sort by decade and by last name within each decade.

984-001

984-002

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