json对象，转化为父类

JsonHelper helper = new JsonHelper();
            Type target = typeof(JsonHelper);
            MethodInfo mi = target.GetMethod("FromJson").MakeGenericMethod(typeof(PatientBaseInfo));
            PatientBaseInfo patient = (PatientBaseInfo)(mi.Invoke(helper, new object[] { patientInfoJson }));
            StringBuilder sb = new StringBuilder();
            sb.AppendFormat("Insert into patient VALUES ('{0}','{1}','{2}','{3}','{4}','{5}','{6}','{7}')",
                patient.ID, patient.Name, patient.Gender, patient.Birthday, deviceType, patient.CardNo, Convert.ToString(patientInfoJson), patient.RegistDate);

 //private static 

        /// <summary>
        /// 从Json 转换成对象
        /// </summary>
        /// <param name="json">json字符串</param>
        /// <returns>实体对象</returns>
        public static T FromJson<T>(string json)
        {
            if (string.IsNullOrEmpty(json))
            {
                return default(T);
            }
            using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(json)))
            {
                DataContractJsonSerializer JSON = new DataContractJsonSerializer(typeof(T));
                var t = JSON.ReadObject(ms);
                return (T)t;
            }
        }