public static class DataSourceRequestExtensions
    {
        /// <summary>
        /// Enable flattened properties in the ViewModel to be used in DataSource.
        /// </summary>
        public static void Deflatten(this DataSourceRequest dataSourceRequest)
        {
            foreach (var filter in dataSourceRequest.Filters)
            {
                Deflatten(filter);
            }

            foreach (var sortDescriptor in dataSourceRequest.Sorts)
            {
                sortDescriptor.Member = DeflattenString(sortDescriptor.Member);
            }
        }

        private static void Deflatten(IFilterDescriptor filter)
        {
            FilterDescriptor filterDescriptor;
            CompositeFilterDescriptor compositeFilterDescriptor;

            if ((filterDescriptor = filter as FilterDescriptor) != null)
                filterDescriptor.Member = DeflattenString(filterDescriptor.Member);
            else if ((compositeFilterDescriptor = filter as CompositeFilterDescriptor) != null)
            {
                foreach(var childFilter in compositeFilterDescriptor.FilterDescriptors)
                    Deflatten(childFilter);
            }
        }

        private static string DeflattenString(string source)
        {
            return source.Replace('_', '.');
        }
    }