Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="FormattingConverter.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//    Converter for formatting short date values.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.Windows.Data;

namespace Catel.Windows.Data.Converters
{
    /// <summary>
	/// Converter for formatting short date values.
	/// </summary>
#if !SILVERLIGHT
    [ValueConversion(typeof(object), typeof(string))]
#endif
    public class FormattingConverter : IValueConverter
    {
        #region Variables
        private readonly string _defaultFormatString;
        #endregion

        #region Constructors
        /// <summary>
        /// Initializes a new instance of the <see cref="FormattingConverter"/> class.
        /// </summary>
        public FormattingConverter()
            : this(string.Empty) { }

        /// <summary>
        /// Initializes a new instance of the <see cref="FormattingConverter"/> class.
        /// </summary>
        /// <param name="defaultFormatString">A default format string.</param>
        protected FormattingConverter(string defaultFormatString)
        {
            _defaultFormatString = defaultFormatString;
        }
        #endregion

        #region Methods
		/// <summary>
		/// Convert to formatted string.
		/// </summary>
		/// <param name="value">A value.</param>
		/// <param name="targetType">Target type.</param>
		/// <param name="parameter">Format string.</param>
		/// <param name="culture">A culture.</param>
		/// <returns>Converted value.</returns>
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            string formatString = string.Format("{{0:{0}}}", (parameter as string) ?? _defaultFormatString);
            return string.Format(culture, formatString, value);
        }

		/// <summary>
		/// Convert back.
		/// </summary>
		/// <param name="value">A value.</param>
		/// <param name="targetType">Target type.</param>
		/// <param name="parameter">Parameter.</param>
		/// <param name="culture">A culture.</param>
		/// <returns>Converted value.</returns>
		/// <remarks>We don't intend this to ever be called.</remarks>
        public virtual object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return ConverterHelper.DoNothingBindingValue;
        }
        #endregion
    }
}