using System;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var jsonStr = @"{

          ""runtimeOptions"": {

            ""tfm"": ""net6.0"",

            ""frameworks"": [

              {

                ""name"": ""Microsoft.NETCore.App"",

                ""version"": ""6.0.0""

              },

              {

                ""name"": ""Microsoft.WindowsDesktop.App"",

                ""version"": ""6.0.0""

              }

            ],

            ""configProperties"": {

              ""MaxTargets"" : ""1024""

           }

          }  

        }";

​

        var result = JsonConvert.DeserializeObject<SomeClassName>(jsonStr);

        Console.WriteLine(result.RuntimeOptions.Tfm);

    }

    public class SomeClassName

    {

        [JsonProperty("runtimeOptions")]

        public OptionalInclude RuntimeOptions { get; set; }

    }

    public class Framework

    {

        [JsonProperty("name")]

        public string Name { get; set; }

​

        [JsonProperty("version")]

        public string Version { get; set; }

    }

    public class ConfigProperties

    {

        [JsonProperty("MaxTargets")]

        public string MaxTargets { get; set; }

    }

    public class OptionalInclude

    {

        [JsonProperty("configProperties")]

        public ConfigProperties ConfigProperties { get; set; }

​

        [JsonProperty("tfm")]

        public string Tfm { get; set; }

​

        [JsonProperty("frameworks")]

        public List<Framework> Frameworks { get; set; }

    }

}