Создание глобальной переменной

JSON-запрос:

{
 "SetRepoParams" : 
  {
   "tMb" : 
    {
     "id" : "S1!M"
    },
   "tArg" : 
    {
     "pattern" : 
      {
       "obInst" : "true",
       "sharedParams" : "Add"
      },
     "meta" : 
      {
       "sharedParams" : 
        {
         "params" : 
          {
           "it" : 
            {
             "k" : "18446744073709551615",
             "id" : "START_PERIOD_D",
             "n" : "Дата начала вычислений",
             "value" : "01.01.2020 00:00",
             "dt" : "4"
            }
          }
        }
      },
     "metaGet" : 
      {
       "obInst" : "true",
       "sharedParams" : "Get"
      }
    }
  }
}

JSON-ответ:

{
 "SetRepoParamsResult" : 
  {
   "id" : 
    {
     "id" : "S1!M"
    },
   "meta" : 
    {
     "sharedParams" : 
      {
       "IsShared" : "1",
       "Url" : "http:\/\/v-shp-development.dev.fs.fsight.world",
       "params" : 
        {
         "it" : 
          [
            {
             "k" : "1",
             "id" : "GLOBAL_INT",
             "n" : "Ограничение",
             "vis" : "1",
             "value" : "600",
             "dt" : "2",
             "binding" : "UI="IntegerEdit""
            },
            {
             "k" : "2",
             "id" : "START_PERIOD_D",
             "n" : "Дата начала вычислений",
             "vis" : "1",
             "value" : "2020-01-01",
             "dt" : "4",
             "binding" : ""
            }
          ]
        }
      }
    }
  }
}

public static RepoParamsResult AddSharedParam(string moniker)
{
    var somClient = new SomPortTypeClient(); //Прокси-объект для выполнения операций
    //Параметры выполнения операции
    var tSet = new SetRepoParams()
    {
        tArg = new SetRepoParamsArg()
        {
            pattern = new RepoParamsMdPattern()
            {
                sharedParams = ListOperation.Add
            },
            meta = new RepoParamsMd()
            {
                sharedParams = new RepoSharedParams()
                {
                    @params = new OdArg[]
                    {
                        new OdArg()
                        {
                            k = ulong.MaxValue,
                            id = "START_PERIOD_D",
                            n = "Дата начала вычислений",
                            value = "01.01.2020 00:00",
                            dt = 4 //DbDataType.DateTime
                        }
                    }
                }
            },
            metaGet = new RepoParamsMdPattern()
            {
                sharedParams = ListOperation.Get
            }
        },
        tMb = new MbId() { id = moniker }
    };
    //Изменение параметров репозитория
    var result = somClient.SetRepoParams(tSet);
    return result;
}