Custom Dictionary to get formatted values based on specific values and rules

gistfile1.cs

using System;
using System.Collections.Generic;

namespace CustomDictionary {
    public interface IGenericDictionarySB<T, TK> {
        T this[TK key] { get; set; }
    }

    public class SuperBidParameters : IGenericDictionarySB<string,string> {
        private string _ageDriver;
        public string this[string key] {
            get { return GetFormattedProperty(key); }
            set { StoreProperty(key, value); }
        }

        private string GetFormattedProperty(string key) {
            string val = null;
            switch (key)
            {
                case "age_driver":
                    val = _ageDriver;
                    break;
            }
            return string.IsNullOrEmpty(val) ? string.Empty : GetProperty(key, val);
        }

        private static string GetProperty(string key, string val) {
             IMatcherFormatter matcherFormatter = MatcherFormatterFactory.GetFormatter(key);
            return matcherFormatter.Format(val);
        }

        private void StoreProperty(string key, string value) {
            switch (key) {
                case "age_driver" :
                    _ageDriver = value;
                    break;                    
            }
        }
    }

    public static class MatcherFormatterFactory {
        public static IMatcherFormatter GetFormatter(string key) {
            switch (key)
            {
                case "age_driver":
                    return new AgeDriverFormatter();
            }
        }
    }
    public interface IMatcherFormatter {
        string Format(string value);
    }
    public class AgeDriverFormatter : IMatcherFormatter {
        private IEnumerable<string> _availableRanges;

        public AgeDriverFormatter() {
            _availableRanges = LoadRanges("age_driver");
        }

        private IEnumerable<string> LoadRanges(string key) {
            return key.Equals("age_driver") ? new []{"20-30"} : null;
        }

        public string Format(string value) {
            if (_availableRanges == null)
                throw new InvalidOperationException("There is no rules to apply format");
            return value;
        }
    }
}