gistfile1.txt

   public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (Converters.Count == 0 && value != null && value.GetType() == targetType)
        {
            return value;
        }
        foreach (IValueConverter converter in Converters)
        {
            object temp = converter.Convert(value, targetType, parameter, culture);
            if (temp != null)
            {
                return temp;
            }
        }
        return null;
    }
    
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (Converters.Count == 0 && value.GetType() == targetType)
        {
            return value;
        }
        foreach (IValueConverter converter in Converters)
        {
            object temp = converter.ConvertBack(value, targetType, parameter, culture);
            if (temp != null)
            {
                return temp;
            }
        }
        return null;
    }