/// <summary>
/// Calls GetContacts(int) to generate a list of randomly constructed Contact objects and groups
/// them into an ObservableCollection of GroupInfoList objects for binding in the ZoomedInView and
/// ZoomedOutView of the SemanticZoom control. This function is not called in this demo, but is provided
/// as an example. It will only generate GroupInfoList objects with Contact members and will not make any Empty
/// GroupInfoList objects. Call this if you don't want to have Empty GroupInfoList members (maybe...remember that the Contact
/// objects are generated randomly so there might be a Contact for every Key/letter), and then your ZoomedOutView
/// will only have GroupInfoList objects representing those Keys (letters) with Contacts in them.
/// </summary>
/// <param name="numberOfContacts"></param>
/// <returns>An ObservableCollection of GroupInfoList objects containing Contact objects.</returns>
public static ObservableCollection <GroupInfoList> GetContactsGrouped(int numberOfContacts)
{
ObservableCollection <GroupInfoList> groups = new ObservableCollection <GroupInfoList>();
// This Linq expression calls GetContacts for a bunch of randomly-generated Contact objects,
// groups them by the first letter of the LastName of each Contact, orders them alphabetically, and makes an
// anonymous type object containing the GroupName (key) and the list of items (Contacts).
var query = from item in GetContacts(numberOfContacts)
group item by item.LastName[0] into g
orderby g.Key
select new { GroupName = g.Key, Items = g };
// This iterates through the query results and makes a GroupInfoList object for each
// group of Contacts represented by a letter.
foreach (var g in query)
{
GroupInfoList info = new GroupInfoList();
// set the Key property of the GroupInfoList to the GroupName of the anonymous type object
// generated in the Linq query above
info.Key = g.GroupName.ToString();
// iterate through all the Contact items in the Linq query and add them
// to the GroupInfoList object derived from List<T>
foreach (var item in g.Items)
{
info.Add(item);
}
// add this GroupInfoList to the ObservableCollection<GroupInfoList> that we will return
groups.Add(info);
}
return(groups);
}
/// <summary>
/// Like GetContactsGrouped, this generates an ObservableCollection of GroupInfoLists, but does it a bit
/// differently. For Contact groups that have no Contact data members, this will generate an empty GroupInfoList
/// object representing the letter (or number), and allow you to display a ZoomedOutView just like the Contacts list
/// on Windows Phone, where empty groups with no Contacts are grayed out and not selectable.
/// </summary>
/// <param name="numberOfContacts"></param>
/// <returns>An ObservableCollection of GroupInfoList objects containing Contact objects.</returns>
public static ObservableCollection <GroupInfoList> GetContactsGroupedAllAlpha(int numberOfContacts)
{
ObservableCollection <GroupInfoList> groups = new ObservableCollection <GroupInfoList>();
// get an ObservableCollection of Contact objects (it could also be a List<Contact>).
var generatedContacts = GetContacts(numberOfContacts);
// the letters/numbers representing our GroupInfoList Keys
var letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToList();
// This Linq expression creates an IEnumerable collection of anonymous types containing the letter/number
// Key of the group, and its associated Contact objects by iterating through the List of letters/numbers
// and getting the Contact objects where the LastName property starts with that letter/number, ordering them
// by LastName.
var groupByAlpha = from letter in letters
select new
{
Key = letter.ToString(),
query = from item in generatedContacts
where item.LastName.StartsWith(letter.ToString(), StringComparison.CurrentCultureIgnoreCase)
orderby item.LastName
select item
};
// Now, we create the GroupInfoList objects and add them to our returned ObservableCollection.
// iterate through the IEnumerable 'groupByAlpha' created above
foreach (var g in groupByAlpha)
{
// make a new GroupInfoList object
GroupInfoList info = new GroupInfoList();
// assign its key (letter/number)
info.Key = g.Key;
// iterate through all the Contact objects for that Key and add them to the GroupInfoList. If the
// Key has no Contacts, then none will be added and that GroupInfoList will be empty.
foreach (var item in g.query)
{
info.Add(item);
}
// add the GroupInfoList to the ObservableCollection to be returned
groups.Add(info);
}
return(groups);
}
