Apply Custom Grouping to a Collection : CollectionViewSource « Windows Presentation Foundation « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Windows Presentation Foundation
3. CollectionViewSource

<Window 
    x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:WpfApplication1="clr-namespace:WpfApplication1"
    Title="WPF" Height="300" Width="160">

    <Window.Resources>
        <WpfApplication1:Countries x:Key="countries"/>
        <WpfApplication1:GroupByContinentConverter x:Key="GroupByContinentConverter"/>
        <CollectionViewSource 
            x:Key="cvs" 
            Source="{Binding Source={StaticResource countries}}">
            <CollectionViewSource.GroupDescriptions>
                <PropertyGroupDescription Converter="{StaticResource GroupByContinentConverter}" />
            </CollectionViewSource.GroupDescriptions>
        </CollectionViewSource>
    </Window.Resources>
    <Grid>
        <ItemsControl ItemsSource="{Binding Source={StaticResource cvs}}" DisplayMemberPath="Name" >
            <ItemsControl.GroupStyle>
                <x:Static Member="GroupStyle.Default"/>
            </ItemsControl.GroupStyle>
        </ItemsControl>

    </Grid>
</Window>
//File:Window.xaml.cs

using System;
using System.Globalization;
using System.Windows.Data;
using System.Collections.ObjectModel;

namespace WpfApplication1
{
    public class GroupByContinentConverter : IValueConverter
    {
        public object Convert(object value,Type targetType,object parameter,CultureInfo culture)
        {
            Country country = (Country)value;
            // Decide which group the country belongs in
            switch (country.Continent)
            {
                case Continent.NorthAmerica:
                    return "Americas";
                default:
                    return "Others";
            }
        }

        public object ConvertBack(object value,Type targetType,object parameter,CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

    public class Country
    {
        private string name;
        private Continent continent;

        public Country(string name, Continent continent)
        {
            this.name = name;
            this.continent = continent;
        }

        public string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
            }
        }

        public Continent Continent
        {
            get
            {
                return continent;
            }
            set
            {
                continent = value;
            }
        }
    }

    public enum Continent
    {
        Europe,
        NorthAmerica,
    }

    public class Countries : Collection<Country>
    {
        public Countries()
        {
            this.Add(new Country("Great Britan", Continent.Europe));
            this.Add(new Country("USA", Continent.NorthAmerica));
            this.Add(new Country("Canada", Continent.NorthAmerica));
        }
    }
}

24.139.CollectionViewSource
	24.139.1.	Use CollectionViewSource to sort and group data in XAML.
	24.139.2.	Create CollectionViewSource
	24.139.3.	Apply Custom Grouping to a Collection