AccordionControl.AllowCollectionView Property

<Window x:Class="CollectionViewSample.MainWindow" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core" 
        xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors" 
        xmlns:dxa="http://schemas.devexpress.com/winfx/2008/xaml/accordion" 
        xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm" 
        xmlns:componentModel="clr-namespace:System.ComponentModel;assembly=WindowsBase" 
        dx:ThemeManager.Theme="Office2019Colorful" 
        xmlns:local="clr-namespace:CollectionViewSample" 
        DataContext="{dxmvvm:ViewModelSource local:ViewModel}" 
        Title="Products" Height="450" Width="500"> 
    <Window.Resources> 
        <CollectionViewSource Source="{Binding Products}" x:Key="Products" > 
            <CollectionViewSource.SortDescriptions> 
                <componentModel:SortDescription PropertyName="ProductName" Direction="Ascending"/> 
            </CollectionViewSource.SortDescriptions> 
            <CollectionViewSource.GroupDescriptions> 
                <PropertyGroupDescription PropertyName="Category"/> 
            </CollectionViewSource.GroupDescriptions> 
        </CollectionViewSource> 
    </Window.Resources> 
    <Grid Margin="5"> 
        <Grid.ColumnDefinitions> 
            <ColumnDefinition/> 
            <ColumnDefinition/> 
        </Grid.ColumnDefinitions> 
        <dxe:ListBoxEdit ItemsSource="{Binding Source={StaticResource Products}}" 
                         DisplayMember="ProductName" 
                         AllowCollectionView="True" IsSynchronizedWithCurrentItem="True"> 
            <dxe:ListBoxEdit.GroupStyle> 
                <x:Static Member="GroupStyle.Default"/> 
            </dxe:ListBoxEdit.GroupStyle> 
        </dxe:ListBoxEdit> 

        <dxa:AccordionControl Grid.Column="1" ItemsSource="{Binding Source={StaticResource Products}}" 
                              AutoExpandAllItems="True" ChildrenPath="Items" 
                              AllowCollectionView="True" IsSynchronizedWithCurrentItem="True" ShowSearchControl="True"> 
            <dxa:AccordionControl.ItemContainerStyle> 
                <Style TargetType="dxa:AccordionItem"> 
                    <Style.Triggers> 
                        <Trigger Property="ItemLevel" Value="1"> 
                            <Setter Property="Header" Value="{Binding ProductName}"/> 
                        </Trigger> 
                    </Style.Triggers> 
                </Style> 
            </dxa:AccordionControl.ItemContainerStyle> 
        </dxa:AccordionControl> 
    </Grid> 
</Window> 

using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace CollectionViewSample {
    public class ViewModel {
        public virtual ReadOnlyCollection<Product> Products { get; set; }

        public ViewModel() {
            Products = new ReadOnlyCollection<Product>(CreateProducts());
        }
        List<Product> CreateProducts() {
            var result = new List<Product> {
                new Product("Queso Manchego La Pastora", "Cheeses"),
                new Product("Gorgonzola Telino", "Cheeses"),
                new Product("Chai", "Beverages"),
                new Product("Outback Lager", "Beverages"),
                new Product("Mozzarella di Giovannia", "Cheeses"),
                new Product("Geitost", "Cheeses"),
                new Product("Chartreuse verte", "Beverages"),
                new Product("Ipoh Coffee", "Beverages")
            };
            return result;
        }
    }
    public class Product {
        public Product(string productName, string category) {
            ProductName = productName;
            Category = category;
        }
        public string ProductName { get; set; }
        public string Category { get; set; }

        public override string ToString() {
            return ProductName;
        }
    }
}

Imports System.Collections.Generic
Imports System.Collections.ObjectModel

Namespace CollectionViewSample
    Public Class ViewModel
        Public Overridable Property Products As ReadOnlyCollection(Of Product)

        Public Sub New()
            Products = New ReadOnlyCollection(Of Product)(CreateProducts())
        End Sub 

        Private Function CreateProducts() As List(Of Product)
            Dim result = New List(Of Product) From {
                New Product("Queso Manchego La Pastora", "Cheeses"),
                New Product("Gorgonzola Telino", "Cheeses"),
                New Product("Chai", "Beverages"),
                New Product("Outback Lager", "Beverages"),
                New Product("Mozzarella di Giovannia", "Cheeses"),
                New Product("Geitost", "Cheeses"),
                New Product("Chartreuse verte", "Beverages"),
                New Product("Ipoh Coffee", "Beverages")
            }
            Return result
        End Function 
    End Class 

    Public Class Product
        Public Sub New(ByVal productName As String, ByVal category As String)
            ProductName = productName
            Category = category
        End Sub 

        Public Property ProductName As String 
        Public Property Category As String 

        Public Overrides Function ToString() As String 
            Return ProductName
        End Function 
    End Class 
End Namespace