ValueConverterGroup with parameters.

ValueConverterGroup.cs

public class ValueConverterGroup : List<IValueConverter>, IValueConverter
{
    private string[] _parameters;
    private bool _shouldReverse = false;

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

        if (_shouldReverse)
        {
            Reverse();
            _shouldReverse = false;
        }

        return this.Aggregate(value, (current, converter) => converter.Convert(current, targetType, GetParameter(converter), culture));
    }

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

        Reverse();
        _shouldReverse = true;

        return this.Aggregate(value, (current, converter) => converter.ConvertBack(current, targetType, GetParameter(converter), culture));
    }

    private void ExtractParameters(object parameter)
    {
        if (parameter != null)
            _parameters = Regex.Split(parameter.ToString(), @"(?<!\\),");
    }

    private string GetParameter(IValueConverter converter)
    {
        if (_parameters == null)
            return null;

        var index = IndexOf(converter as IValueConverter);
        string parameter;

        try
        {
            parameter = _parameters[index];
        }

        catch (IndexOutOfRangeException ex)
        {
            parameter = null;
        }

        if (parameter != null)
            parameter = Regex.Unescape(parameter);

        return parameter;
    }
}

Hi,
Thanks for this code. It helped.
I’m wondering., shouldn’t parameter be reversed as well?
Thanks,
Igor

Hi @IGonza,

I think you are right. I shall try to update the snippet as soon as possible.

Thanks,

Trevi

ConvertBack has a bug, hasn't it? You always call Reverse(), so if ConvertBack is called twice the second time it will use the original order not the reversed. I would remove the _shouldReverse logic and simply user ((IEnumerable<IValueConverter>)this).Reverse(). It does not mutate the list.