Dictionary with index

class IndexedDictionary<KEY, VALUE> : System.Collections.Generic.Dictionary<KEY, VALUE> {
    public VALUE this[int index] { get { return GetValueByIndex(index); } }
    VALUE GetValueByIndex(int index) {
        int current = 0;
        foreach (VALUE value in Values) {
            if (current == index)
                return value;
            ++index;
        }
        throw new System.IndexOutOfRangeException();
    } //GetByIndex */
} //IndexedDictionary

class IndexedDictionary<KEY, VALUE> : System.Collections.Generic.Dictionary<KEY, VALUE> {
    public VALUE this[int index] { get { return Index[index]; } }
    new public void Add(KEY key, VALUE value) {
        base.Add(key, value);
        RebuildIndex();
    } //Add
    new public void Remove(KEY key) {
        base.Remove(key);
        RebuildIndex();
    } //AddRange
    new public void Clear() {
        base.Clear();
        RebuildIndex();
    } //Clear
    void RebuildIndex() {
        Index = new VALUE[this.Keys.Count];
        if (this.Values.Count > 0)
            this.Values.CopyTo(Index, 0);
    } //RebuildIndex
    KEY[] Index = new KEY[0];
} //IndexedDictionary