GameFramework.DataDML.LoadSingleTableFriendInfo C# (CSharp) Method

        private static GeneralRecordData LoadSingleTableFriendInfo(List<string> primaryKeys)
        {
            GeneralRecordData ret = null;
            try {
              using (MySqlCommand cmd = new MySqlCommand()) {
                cmd.Connection = DBConn.MySqlConn;
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.CommandText = "LoadSingleTableFriendInfo";
                if(primaryKeys.Count != 1)
                    throw new Exception("primary key number don't match !!!");
                MySqlParameter inputParam;
                inputParam = new MySqlParameter("@_Guid", MySqlDbType.UInt64);
                inputParam.Direction = ParameterDirection.Input;
                inputParam.Value = (ulong)Convert.ChangeType(primaryKeys[0],typeof(ulong));
                cmd.Parameters.Add(inputParam);
                using (DbDataReader reader = cmd.ExecuteReader()) {
                  if (reader.Read()) {
                    ret = new GeneralRecordData();
                    object val;
                    TableFriendInfo msg = new TableFriendInfo();
                    val = reader["Guid"];
                    msg.Guid = (ulong)val;
                    ret.PrimaryKeys.Add(val.ToString());
                    val = reader["UserGuid"];
                    msg.UserGuid = (ulong)val;
                    ret.ForeignKeys.Add(val.ToString());
                    val = reader["FriendGuid"];
                    msg.FriendGuid = (ulong)val;
                    val = reader["FriendNickname"];
                    msg.FriendNickname = (string)val;
                    val = reader["QQ"];
                    msg.QQ = (long)val;
                    val = reader["weixin"];
                    msg.weixin = (long)val;
                    val = reader["IsBlack"];
                    msg.IsBlack = (bool)val;
                    ret.DataVersion = (int)reader["DataVersion"];
                    ret.Data = DbDataSerializer.Encode(msg);
                  }
                }
              }
            } catch (Exception ex) {
              DBConn.Close();
              throw ex;
            }
            return ret;
        }