public class myDictionary : IDictionary<string, Object>
    {
        private IDictionary<string, Object> myDictionary;
        private IList <string> myKey;

        public myDictionary()
        {
            myDictionary=new Dictionary<string, Object>();
            myKey = new List<string>();
        }

        public void Add(string key, object value)
        {
            myDictionary.Add(key, value);
            myKey.Add(key);
        }
        public object this[string key]
        {
            get
            {
                return myDictionary[key];
            }
            set
            {
                myDictionary[key] = value;
            }
        }
        public object this[int index]
        {
            get
            {
                return myDictionary[myKey[index]];
            }
            set
            {
                myDictionary[myKey[index]] = value;
            }
        }
     #region IDictionary其他方法
    ///这里的自己写吧。。
     #endregion 
}