Modifications to JSON file

using (FileStream fs = new FileStream("user.json", FileMode.Open, FileAccess.Read))
                    using (StreamReader sr = new StreamReader(fs))
                    using (JsonTextReader reader = new JsonTextReader(sr))
                    {
                        while (reader.Read())
                        {
                            if (reader.TokenType == JsonToken.StartObject)
                            {
                                // Load each object from the stream and do something with it
                                JObject obj = JObject.Load(reader);
                                SqlCommand cmd = null;
		   con.Open();
                                string cb = "insert into user(userid,name) VALUES ('" + obj["userid"] + "','" + obj["name"] + "')";
                                cmd = new SqlCommand(cb);
                                cmd.Connection = con;
                                cmd.ExecuteNonQuery();
		   con.Close();
                            }
                        }
                    }