using System;

using Newtonsoft.Json;

​

public class SubModel {

    public string Field1 {get;set;}

    public string Field2 {get;set;}

}

​

public class DataModel {

    public SubModel SubModel {get;set;}

    public dynamic Payload {get;set;}

}

​

public class Program

{

    public static void Main()

    {

        DataModel model = new DataModel() {

            SubModel = new SubModel() {

                Field1 = "hello",

                Field2 = "world"

            },

            Payload = new {

                Author="Albert",

                BookCount = 3,

                LastSeen = DateTime.Now

            }

        };

        Console.WriteLine(JsonConvert.SerializeObject(model));

        string json = @"{""SubModel"":{""Field1"":""hello"",""Field2"":""world""},""Payload"":{""Author"":""Albert"",""BookCount"":3,""LastSeen"":""2022-09-20T13:01:52.9953791+00:00""}}";

        DataModel newModel = JsonConvert.DeserializeObject<DataModel>(json);

        Console.WriteLine($"SubModel.Field1 {newModel.SubModel.Field1}");

        Console.WriteLine($"SubModel.Field2 {newModel.SubModel.Field2}");

        Console.WriteLine($"Payload.Author {newModel.Payload.Author}");

        Console.WriteLine($"Payload.BookCount {newModel.Payload.BookCount}");

        Console.WriteLine($"Payload.LastSeen {newModel.Payload.LastSeen}");

    }

}