Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="MultiplyConverter.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   Calculate the product of given value and factor in parameter.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.Windows.Data;

namespace Catel.Windows.Data.Converters
{
    /// <summary>
    /// Calculate the product of given value and factor in parameter.
    /// </summary>
#if !SILVERLIGHT
    [ValueConversion(typeof(int), typeof(int))]
#endif
    public class MultiplyConverter : IValueConverter
    {
        /// <summary>
        /// Calulate the product of given value and factor in parameter.
        /// </summary>
        /// <param name="value">Base value.</param>
        /// <param name="targetType">Not used, supports now int and double.</param>
        /// <param name="parameter">Factor used for multiply (always double).</param>
        /// <param name="culture">Not used.</param>
        /// <returns>Product of specified values.</returns>
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            // Get typed value
            double typedValue = 0d;

            // Check input
            if (value is int)
            {
                typedValue = System.Convert.ToDouble((int)value);
            }
            else if (value is double)
            {
                typedValue = (double)value;
            }

            // Check value
            if (typedValue == 0d)
            {
                return 0d;
            }

            // Get factor
            double factor;
            if (!double.TryParse(parameter as string, out factor))
            {
                return 0d;
            }

            // Multiply
            return typedValue * factor;
        }

        /// <summary>
        /// Calculate value back.
        /// </summary>
        /// <param name="value">Base value.</param>
        /// <param name="targetType">Not used, supports now int and double.</param>
        /// <param name="parameter">Factor used for multiply (always double).</param>
        /// <param name="culture">Not used.</param>
        /// <returns>Original value.</returns>
        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            // Get typed value
            double typedValue = 0d;

            // Check input
            if (value is int)
            {
                typedValue = System.Convert.ToDouble((int)value);
            }
            else if (value is double)
            {
                typedValue = (double)value;
            }

            // Check value
            if (typedValue == 0d)
            {
                return 0d;
            }

            // Get factor
            double factor;
            if (!double.TryParse(parameter as string, out factor))
            {
                return 0d;
            }

            // Divide
            return typedValue / factor;
        }
    }
}