parsing issue with JSON data from SQL 2017 to MongoDB - json

Question

I am working on c# utility to migrate data from SQL server 2017 to MongoDB. Below are steps I am following
1) Getting data from SQL server in JSON format (FOR JSON AUTO)
2) Parsing into BSON document
3) Then trying to insert into MongoDB
But I am getting error while reading JSON data from SQL.
My Json data is combination of root attributes as well as nested objects.
So Its dynamic data, that I want to PUSH as it is to MongoDB.
string jsonData = string.Empty;
foreach (var userId in userIdList)
{
using (SqlConnection con = new SqlConnection("Data Source=;Initial Catalog=;Integrated Security=True"))
{
using (SqlCommand cmd = new SqlCommand("Usp_GetUserdata", con))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("#userId", SqlDbType.Int).Value = userId;
con.Open();
var reader = cmd.ExecuteReader();
jsonResult = new StringBuilder();
//cmd.ExecuteNonQuery();
if (!reader.HasRows)
{
jsonResult.Append("[]");
}
else
{
while (reader.Read())
{
jsonResult.Append(reader.GetValue(0));
jsonData = reader.GetValue(0).ToString();
File.WriteAllText(#"c:\a.txt", jsonResult.ToString());
File.WriteAllText(#"c:\a.txt",jsonData);
jsonData.TrimEnd(']');
jsonData.TrimStart('[');
//Create client connection to our MongoDB database
var client = new MongoClient(MongoDBConnectionString);
//Create a session object that is used when leveraging transactions
var session = client.StartSession();
//Create the collection object that represents the "products" collection
var employeeCollection = session.Client.GetDatabase("mongodev").GetCollection<BsonDocument>("EmpData");
//Begin transaction
session.StartTransaction();
try
{
dynamic resultJson = JsonConvert.DeserializeObject(result);
var document = BsonSerializer.Deserialize<BsonDocument>(resultJson);
//MongoDB.Bson.BsonDocument document
// = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonDocument>(jsonResult);
employeeCollection.InsertOneAsync(document);
//BsonArray pipeline =
// MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonArray>(jsonData);
//var documents = pipeline.Select(val => val.AsBsonDocument);
//employeeCollection.InsertManyAsync(documents);
session.CommitTransaction();
}
catch (Exception e)
{
Console.WriteLine(e);
session.AbortTransaction();
throw;
}
}
}
}
}
}