Grouping GridView in Windows 8 Metro App

Question

Can someone give me some hints how to accomplish the grouping within a GridView for Metro Apps as shown in the Screenshot below.

Answer 1

I may have a solution. In my projet, I had to create a list of contacts in alphabetic order, like the People app.

I used a GridView (with this sample), a CollectionViewSource and a wrappanel I found in the WinRT XAML Toolkit (you can get with NuGet package or copy/paste the source code). It allow you to put your items in columns.

Example

ViewModel

class ContactListViewModel
    {

        public ContactListViewModel()
        {
            ContactSource = new CollectionViewSource();
            Contacts = new ObservableCollection();

            Contacts.Add(new Contact("Gates","Bill"));
            Contacts.Add(new Contact("Bush","Georges"));
            Contacts.Add(new Contact("Obama","Barack"));
            Contacts.Add(new Contact("Hollande","François"));
            Contacts.Add(new Contact("Affleck","Ben"));
            Contacts.Add(new Contact("Allen","Woody"));
            Contacts.Add(new Contact("Hendrix","Jimi"));
            Contacts.Add(new Contact("Harrison", "Georges"));

            Contacts = new ObservableCollection(Contacts.OrderBy(c => c.Name));
            ContactSource.Source = GetGroupsByLetter();
            ContactSource.IsSourceGrouped = true;

        }

        #region Contacts
        public ObservableCollection Contacts
        {
            get;
            protected set;
        }

        public CollectionViewSource ContactSource
        {
            get;
            protected set;
        }
        #endregion


        internal List> GetGroupsByLetter()
        {
            List> groups = new List>();

            var query = from item in Contacts
                        orderby ((Contact)item).Name
                        group item by ((Contact)item).Name[0] into g
                        select new { GroupName = g.Key, Items = g };
            foreach (var g in query)
            {
                GroupInfoList