Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="BooleanToVisibilityConverter.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   Convert from bool to <see cref="T:System.Windows.Visibility" /> and back.
//   The bool value true will be converted to Visibility.Visible.
//   The converted value for bool value false depends on the Visibility value given on construction of the object.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.Windows;
using System.Windows.Data;

namespace Catel.Windows.Data.Converters
{
	/// <summary>
	/// Convert from bool to <see cref="T:System.Windows.Visibility" /> and back.
	/// The bool value true will be converted to Visibility.Visible.
	/// The bool value false will be converted to Visibility.Collapsed.
	/// </summary>
#if !SILVERLIGHT
	[ValueConversion(typeof(bool), typeof(Visibility))]
#endif
    public class BooleanToCollapsingVisibilityConverter : VisibilityConverterBase
    {
        #region Constructor & destructor
        /// <summary>
        /// Initializes a new instance of the <see cref="BooleanToCollapsingVisibilityConverter"/> class.
        /// </summary>
        public BooleanToCollapsingVisibilityConverter()
            : base(Visibility.Collapsed) { }

        /// <summary>
        /// Initializes a new instance of the <see cref="BooleanToCollapsingVisibilityConverter"/> class.
        /// </summary>
        /// <param name="notVisibleVisibility">The <see cref="Visibility"/> state when not visibible should be returned.</param>
        /// <exception cref="ArgumentException">when <paramref name="notVisibleVisibility"/> is <see cref="Visibility.Visible"/>.</exception>
        internal BooleanToCollapsingVisibilityConverter(Visibility notVisibleVisibility)
            : base(notVisibleVisibility) { }
        #endregion

        /// <summary>
        /// Determines what value this converter should return.
        /// </summary>
        /// <param name="value">The value produced by the binding source.</param>
        /// <param name="targetType">The type of the binding target property.</param>
        /// <param name="parameter">The converter parameter to use.</param>
        /// <param name="culture">The culture to use in the converter.</param>
        /// <returns>
        /// 	<c>true</c> if the specified value is visible; otherwise, <c>false</c>.
        /// </returns>
        public override bool IsVisible(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            // Get the parameter
            bool? param = null;
            bool tmp;

            if (parameter != null && bool.TryParse(parameter.ToString(), out tmp))
            {
                param = tmp;
            }

            if (value is bool)
            {
                if (!param.HasValue)
                {
                    // Convert the regular way
                    return (bool) value;
                }

                // Convert by comparing the value and the param
                return ((bool)value == param.Value);
            }

            // Not visible by default
            return false;
        }

        /// <summary>
        /// Convert Visibility back to bool.
        /// </summary>
        /// <param name="value">A value. Only value of type <see cref="T:System.Windows.Visibility" /> is supported,</param>
        /// <param name="targetType">A targettype, currently not used.</param>
        /// <param name="parameter">A parameter value, currently not used.</param>
        /// <param name="culture">A culture, currently not used.</param>
        /// <returns>
        /// When value is Visibility.Visible then true else false.
        /// </returns>
        public override object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            // Get the parameter
            bool? param = null;
            bool tmp;

            if (parameter != null && bool.TryParse(parameter.ToString(), out tmp))
            {
                param = tmp;
            }

            if (value is Visibility)
            {
                bool isVisible = (Visibility)value == Visibility.Visible;

                if (param.HasValue)
                {
                    return isVisible == param;
                }

                return isVisible;
            }

            // Not visible
            return false;
        }
    }

#if !SILVERLIGHT
	/// <summary>
	/// Convert from bool to <see cref="T:System.Windows.Visibility" /> and back.
	/// The bool value true will be converted to Visibility.Visible.
	/// The bool value false will be converted to Visibility.Hidden.
	/// </summary>
	[ValueConversion(typeof(bool), typeof(Visibility))]
    public class BooleanToHidingVisibilityConverter : BooleanToCollapsingVisibilityConverter
    {
		/// <summary>
		/// Default constructor.
		/// </summary>
        public BooleanToHidingVisibilityConverter()
            : base(Visibility.Hidden) { }
    }
#endif
}