Simple WPF Page Transitions

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;

namespace WpfPageTransitions
{
	class InvertConverter : IValueConverter
	{
		public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
		{
			return -(double)value;
		}

		public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
		{
			throw new NotImplementedException();
		}
	}
}