Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="StringToIntConverter.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   Convert string value to int
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.Windows.Data;

namespace Catel.Windows.Data.Converters
{
	/// <summary>
	/// Convert string value to int
	/// </summary>
	/// <remarks></remarks>
#if !SILVERLIGHT
	[ValueConversion(typeof(string), typeof(int?))]
#endif
	public class StringToIntConverter : IValueConverter
	{
		/// <summary>
		/// Convert a string to int value. 
		/// </summary>
		/// <param name="value">string are supported.</param>
		/// <param name="targetType">Only int? is supported.</param>
		/// <param name="parameter">Not supported.</param>
		/// <param name="culture">Not supported.</param>
		/// <returns>When value is not an int the targetValue will be null on construction.</returns>
		public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
		{
			return value != null ? value.ToString() : String.Empty;
		}

		/// <summary>
		/// This method isn't supported.
		/// </summary>
		/// <param name="value">Not used.</param>
		/// <param name="targetType">Not used.</param>
		/// <param name="parameter">Not used.</param>
		/// <param name="culture">Not used.</param>
		/// <returns>Always null.</returns>
		public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
		{
			int tmp = 0;
			int? result = null;

			if (int.TryParse(value as string, out tmp))
			{
				result = tmp;
			}

			return result;
		}
	}
}