using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Foggy.Converters

{

    using System.Windows;

    using System.Windows.Data;



    /// <summary>

    /// Workaround for a bug in the WPF DataGrid (WPF Toolkit version).

    /// </summary>

    /// <remarks>The WPF DataGrid (WPF Toolkit version) throws a FormatException if a view model

    /// includes a SelectedItem property. This value converter works aroun that bug. The value

    /// converter is taken from Nigel Spencer's Blog, which identifies the bug and provides this

    /// solution. See: http://blog.spencen.com/2009/04/30/problems-binding-to-selectedvalue-with-microsoftrsquos-wpf-datagrid.aspx?results=1(</remarks>

    public class IgnoreNewItemPlaceHolderConverter : IValueConverter

    {

        /// <summary>

        /// New item placeholder name

        /// </summary>

        private const string NewItemPlaceholderName = "{NewItemPlaceholder}";



        /// <summary>

        /// Converts a value.

        /// </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>

        /// A converted value. If the method returns null, the valid null value is used.

        /// </returns>

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

        {

            return value;

        }



        /// <summary>

        /// Converts a value.

        /// </summary>

        /// <param name="value">The value that is produced by the binding target.</param>

        /// <param name="targetType">The type to convert to.</param>

        /// <param name="parameter">The converter parameter to use.</param>

        /// <param name="culture">The culture to use in the converter.</param>

        /// <returns>

        /// A converted value. If the method returns null, the valid null value is used.

        /// </returns>

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

        {

            if (value != null && value.ToString() == NewItemPlaceholderName)

            {

                value = DependencyProperty.UnsetValue;

            }



            return value;

        }

    }

}