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}"

BooleanToVisibilityConverterMarkupExtension

public class BooleanToVisibilityConverterMarkupExtension : MarkupExtension, IValueConverter
{
    private static BooleanToVisibilityConverterMarkupExtension converter;

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
       return converter ?? (converter = new BooleanToVisibilityConverterMarkupExtension());
    }

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var v = (bool?)value;
        return v.HasValue && v.Value ? Visibility.Visible : Visibility.Collapsed;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var v = (Visibility)value;
        return v == Visibility.Visible;
    }
}
 
<!-- usage in xaml -->
Visibility="{Binding IsVisible, Converter={converters:BooleanToVisibilityConverterMarkupExtension}}">>