Get a Jump on Navigation in Windows Phone with the LongListSelector: Listing 2.
The ListToGroupedListConverter to group list items.
- By Nick Randolph
- 11/01/2012
public class ListToGroupedListConverter:IValueConverter
{
public const string Alphabet = "abcdefghijklmnopqrstuvwxyz";
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
if(!(value is IEnumerable))return new Group <object >[]{};
var listOfItems = value as IEnumerable;
var first = listOfItems.OfType <object >().FirstOrDefault();
if (first==null) return new Group <object >[] { };
var itemType = first.GetType();
var keyProperty = itemType.GetProperty(parameter as string);
var grouped = (from ing in listOfItems.OfType <object >()
let keyValue = keyProperty.GetValue(ing,null) as string
group ing by keyValue.ToLower()[0]
into gd
select gd).ToArray();
var groups = (from letter in Alphabet
let set = grouped.FirstOrDefault(grouping = > grouping.Key == letter)
select new Group <object >(letter.ToString(), set)).ToArray();
return groups;
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
return null;
}
}
About the Author
Nick Randolph runs Built to Roam, a consulting company that specializes in training, mentoring and assisting other companies build mobile applications. With a heritage in rich client applications for both the desktop and a variety of mobile platforms, Nick currently presents, writes and educates on the Windows Phone platform.