DateTimeFormatterConverter for WinRT

With there being no StringFormat on a binding in WinRT yet you can use this converter to leverage the crazy (different) DateTimeFormatter object:

    public class DateTimeFormatterConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, string language)
        {
            var formatter = new Windows.Globalization.DateTimeFormatting.DateTimeFormatter(parameter.ToString());
            return formatter.Format((DateTime)value);
        }

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

Usage:

<converters1:DateTimeFormatterConverter x:Key="DateTimeFormatterConverter" />

<TextBlock Text="{Binding DealDate, 
                               Converter={StaticResource DateTimeFormatterConverter},
                               ConverterParameter=day month year}"