Sample XAML ListView Grouping for WP8.1

GroupedListPage.xaml

<Page
    x:Class="ListViewSamples.CS.Step1.GroupedListPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ListViewSamples.CS.Step1"
    xmlns:model="using:ListViewSamples.CS.Model"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
    Loaded="Page_Loaded">

    <Page.Resources>
        <Style x:Key="RegionContainerStyle" TargetType="ListViewHeaderItem">
            <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
        </Style>
        <DataTemplate x:Key="RegionTemplate">
            <Border Background="Red">
                <TextBlock Text="{Binding Name}" Foreground="White" FontSize="28"/>
            </Border>
        </DataTemplate>
        <DataTemplate x:Name="DesignationTemplate">
            <TextBlock Text="{Binding Name}" FontSize="24" />
        </DataTemplate>
        <model:GroupedModel x:Key="VM"/>
        <CollectionViewSource x:Key="CVS" Source="{Binding Regions, Source={StaticResource VM}}"
                              IsSourceGrouped="True"
                              ItemsPath="Designations"/>
    </Page.Resources>
    <Grid>
        <ListView x:Name="TheListView"
          ItemsSource="{Binding Source={StaticResource CVS}}"
                  ItemTemplate="{StaticResource DesignationTemplate}"
        >
            <ListView.GroupStyle>
                <GroupStyle HeaderTemplate="{StaticResource RegionTemplate}"
                            HeaderContainerStyle="{StaticResource RegionContainerStyle}"
                            />
            </ListView.GroupStyle>
        </ListView>
    </Grid>
</Page>



using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Storage;

namespace ListViewSamples.CS.Model
{
    public class GroupedModel : BindableObject
    {
        private ObservableCollection<Region> _regions;
        public ObservableCollection<Region> Regions
        {
            get { return _regions; }
            set { SetProperty(ref _regions, value); }
        }

        public GroupedModel()
        {
            LoadDesignData();
        }

        [Conditional("DESIGN")]
        void LoadDesignData()
        {
            ObservableCollection<Region> tmp = new ObservableCollection<Region>();
            Region bordeaux = new Region("Bordeaux");
            tmp.Add(bordeaux);
            bordeaux.Designations.Add(new Designation("Loupiac") { Region = bordeaux });
            bordeaux.Designations.Add(new Designation("Moulis") { Region = bordeaux });
            Region bourgogne = new Region("Bourgogne");
            tmp.Add(bourgogne);
            bourgogne.Designations.Add(new Designation("Chambolle-Musigny") { Region = bourgogne });
            bourgogne.Designations.Add(new Designation("Gevrey-Chambertin") { Region = bourgogne });
            bourgogne.Designations.Add(new Designation("Nuits-Saint-Georges") { Region = bourgogne });

            Regions = tmp;
        }

        public async void LoadData(Uri fileUri)
        {
            ObservableCollection<Region> tmp = new ObservableCollection<Region>();
            var storageFile = await StorageFile.GetFileFromApplicationUriAsync(fileUri);
            using (var stream = await WindowsRuntimeStorageExtensions.OpenStreamForReadAsync(storageFile))
            {
                var doc = System.Xml.Linq.XDocument.Load(stream);
                foreach (var regionNode in doc.Descendants("Region"))
                {
                    Region region = new Region(regionNode.Attribute("Name").Value);
                    tmp.Add(region);
                    foreach (var designationNode in regionNode.Descendants("Designation"))
                    {
                        Designation designation = new Designation(designationNode.Attribute("Name").Value) { Region = region };
                        region.Designations.Add(designation);
                    }
                }
            }
            Regions = tmp;
        }
    }
}