using MongoDB.Bson;

using MongoDB.Bson.Serialization;

using MongoDB.Bson.Serialization.Attributes;

using System;

​

namespace testBson

{

    [BsonIgnoreExtraElements]

    public class MongoDbLogModel

    {

        public string Level { get; set; }

​

        public string RenderedMessage { get; set; }

​

        [BsonDateTimeOptions(Kind = DateTimeKind.Local)]

        public DateTime? Timestamp { get; set; }

​

        [BsonDateTimeOptions(Kind = DateTimeKind.Local)]

        public DateTime UtcTimeStamp { get; set; }

        public BsonDocument Properties { get; set; }

        [BsonElement("Exception")]

        public BsonDocument Exception { get; set; }

    }

    class Program

    {

        static void Main(string[] args)

        {

            var json = @"{

                          ""_id"": { ""$oid"": ""61a8dadd1ab0e48d55b06626"" },

                          ""Level"": ""Error"",

                          ""UtcTimeStamp"": { ""$date"": ""2021-12-02T14:40:30.436Z"" },

                          ""MessageTemplate"": { },

                          ""RenderedMessage"": """",

                          ""Properties"": { },

                          ""Exception"": {

                                        ""_t"": ""SqlException"",

                            ""HelpLink"": null,

                            ""Source"": ""Core Microsoft SqlClient Data Provider"",

                            ""HResult"": -2146232060,

                            ""Message"": ""Invalid object name 'SystemControlLogs'."",

                            ""StackTrace"": ""   at Microsoft.Data.SqlClien"",

                            ""Data"": { }

                                    }

                                }";

            BsonClassMap.RegisterClassMap<MongoDbLogModel>();

​

            var document = BsonSerializer.Deserialize<MongoDbLogModel>(json);

            Console.WriteLine(string.Join(',',document.Exception.ToDictionary().Keys));

    }

    }

}

​