在泛型类中写一个Dictionary属性，用来接收附加参数

protected IDictionary<string, object> _outputValues = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);

        /// <summary>
        /// 附加参数
        /// </summary>
        public IDictionary<string, object> OutputValues
        {
            get
            {
                return _outputValues;
            }
        }

        /// <summary>
        /// 获取返回值的附加参数
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public TM GetOutputValue<TM>(string key)
        {
            TM temp = default(TM);
            if (!OutputValues.IsNullOrEmpty() && OutputValues.ContainsKey(key))
            {
                temp = (TM)OutputValues[key];
            }
            return temp;
        }

        /// <summary>
        /// 设置返回值的附加参数
        /// </summary>
        /// <param name="key"></param>
        /// <param name="value"></param>
        public void SetOutputValue<TM>(string key, TM value)
        {
            OutputValues[key] = value;
        }