private static IEnumerable <Employee> FilterDateField(KeyValuePair <string, object> filterProp, IEnumerable <Employee> employees)
        {
            var      dateSearchProps = (Dictionary <string, DateTime?>)filterProp.Value;
            DateTime?minDate         = dateSearchProps["MinDate"];
            DateTime?maxDate         = dateSearchProps["MaxDate"];

            switch (filterProp.Key)
            {
            case "DateOfBirth":
                if (minDate.HasValue && SqlHelpers.IsValidSqlDate(minDate.Value))
                {
                    employees = employees.Where(l => l.DateOfBirth >= minDate);
                }
                if (maxDate.HasValue && SqlHelpers.IsValidSqlDate(maxDate.Value))
                {
                    employees = employees.Where(l => l.DateOfBirth < maxDate.Value.Date.AddDays(1));
                }
                break;
            }

            return(employees);
        }