c# DataReader转换为Json

 /// <summary> 
        /// DataReader转换为Json 
        /// </summary> 
        /// <param name="dataReader">DataReader对象</param> 
        /// <returns>Json字符串</returns> 
        public static string ToJson(DbDataReader dataReader)
        {
            StringBuilder jsonString = new StringBuilder();
            jsonString.Append("[");
            while (dataReader.Read())
            {
                jsonString.Append("{");
                for (int i = 0; i < dataReader.FieldCount; i++)
                {
                    Type type = dataReader.GetFieldType(i);
                    string strKey = dataReader.GetName(i);
                    string strValue = dataReader[i].ToString();
                    jsonString.Append("\"" + strKey + "\":");
                    strValue = String.Format(strValue, type);
                    if (i < dataReader.FieldCount - 1)
                    {
                        jsonString.Append(strValue + ",");
                    }
                    else
                    {
                        jsonString.Append(strValue);
                    }
                }
                jsonString.Append("},");
            }
            dataReader.Close();
            jsonString.Remove(jsonString.Length - 1, 1);
            jsonString.Append("]");
            return jsonString.ToString();
        }