Get a Jump on Navigation in Windows Phone with the LongListSelector: Listing 2.

The ListToGroupedListConverter to group list items.

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.