How to retrieve the data from mongodb in json format

Question

I am retrieving the data from mongodb.it is coming as bson document.

when i am converting it to json it throws system out of memory exception because of bulk data(lakhs of data) is coming from mongodb.

Is it possible to retrieve the data from mongodb in json format directly? how to resolve this.Any Help.Thanks in Advance.

please see the image.

 

public object getFrequencyQuestionData1(int id)
       {
           var StudyId = (from ST in _context.Study_Team
                          where ST.Emp_Id == id
                          select (ST.Study_Id).ToString()).ToList();
           var connectionString = "mongodb://localhost:27017";
           MongoClient client = new MongoClient(connectionString);
           MongoServer server = client.GetServer();
           MongoDatabase db = server.GetDatabase("FormDataBase");
           MongoCollection<BsonDocument> collection = db.GetCollection<BsonDocument>("FrequencyQuestionForm");
           var array = new BsonArray(StudyId.ToArray());
           var query = Query.In("data.formList.IdentificationDetails.Study_Id", array);
           var myLists = collection.Find(query);
           myLists.SetFields(Fields.Include("_id","data.formList.IdentificationDetails.Study_Id", "data.formList.IdentificationDetails.Study_Name", "data.formList.IdentificationDetails.Volunteer_Id", "data.formList.IdentificationDetails.Form_Id","data.formList.IdentificationDetails.Form_Name", "data.formList.IdentificationDetails.Status", "data.formList.IdentificationDetails.Group_Id", "data.formList.IdentificationDetails.Visit_No","data.formList.IdentificationDetails.Created_Emp_Id", "data.formList.IdentificationDetails.Updated_Emp_Id"));
           var items = myLists.ToList();
           string document = items.ToJson();
           JToken token = JToken.Parse(document);
           var jObject = JObject.FromObject(new { formdata = token });
           JArray sizes = (JArray)jObject["formdata"];
           ArrayList SplittedData = new ArrayList();
           for (int i = 0; i < sizes.Count(); i++)
           {
               JValue _id = (JValue)sizes[i]["_id"];
               JObject sampledata = (JObject)sizes[i]["data"];
               JArray sampledata2 = (JArray)sampledata["formList"];
               JArray sampledata3 = (JArray)sampledata2[0]["IdentificationDetails"];
               sampledata3[0]["id"] = _id;
               int? Visit_No = (int?)sampledata3[0]["Visit_No"];
               int? Group_Id = (int?)sampledata3[0]["Group_Id"];
               int? Study_Id = (int?)sampledata3[0]["Study_Id"];
               int? Form_Id = (int?)sampledata3[0]["Form_Id"];
               int CreatedEmp_Id =(int)sampledata3[0]["Created_Emp_Id"];
               var Visit_No1 = (from SS in _context.Study_Schedule
                                join SV in _context.Study_Visits
                                on new { SS.Study_Id, SS.Visit_No } equals
                                   new { SV.Study_Id, SV.Visit_No }
                                //on SS.Study_Id equals SV.Study_Id && SS.Visit_No equals SV.Visit_No
                                where SS.Study_Id == Study_Id && SS.Visit_No == Visit_No && SS.Form_Id == Form_Id
                                select SV.Visit_Description).FirstOrDefault();
               var Created_Emp_Id = (from US in _context.User
                                     where US.Emp_Id == CreatedEmp_Id
                                     select US.Emp_Name).FirstOrDefault();

               sampledata3[0]["Created_Emp_Id"] = Created_Emp_Id;
               if (Group_Id == null)
               {
                   sampledata3[0]["Diet_Group"] = "";
               }
               else
               {
                   var StudyGroup = (from SG in _context.Study_Group
                                     where SG.Group_Id == Group_Id
                                     select new
                                     {
                                         Group_Description = SG.Group_Description,
                                     }).FirstOrDefault();
                   if (StudyGroup == null)
                   {
                       sampledata3[0]["Diet_Group"] = "";
                   }
                   else
                   {
                       sampledata3[0]["Diet_Group"] = StudyGroup.Group_Description.ToString();
                   }
               }
               sampledata3[0]["Visit"] = Visit_No1;
               sampledata3[0]["Created_Emp_Id"] = Created_Emp_Id;
               var  sampledata4 =  (JObject)sampledata3[0];
               SplittedData.Add(sampledata4);
           }
           var jObject1 = JObject.FromObject(new { formdata = SplittedData});
           return jObject1;
       }