using System;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    const string jsonString = "{\"LogFieldsMapping\": {\"IDField\": { \"FieldName\": \"_id\" },\"LevelField\": {\"FieldName\": \"_source.level\",\"FieldValue\": [{ \"value\": \"Information\" },{ \"value\": \"Error\" }]}}}";

    public static void Main()

    {

        Root queryObject = new();

        Root2 json = JsonConvert.DeserializeObject<Root2>(jsonString);

        foreach(FieldValue fieldValue in json.LogFieldsMapping.LevelField.FieldValue) {

            queryObject.query.@bool.should.Add(

                new Should() {

                    match = new() {

                        level = fieldValue.value

                    }

                }

            );

        }

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

        // Outputs: {"size":1000,"query":{"bool":{"should":[{"match":{"level":"Information"}},{"match":{"level":"Error"}}],"filter":null,"minimum_should_match":0}}}

    }

}

​

// Root myDeserializedClass = JsonConvert.DeserializeObject<Root>(myJsonResponse); 

    public class Match

    {

        public string level { get; set; }

    }

​

    public class Should

    {

        public Match match { get; set; }

    }

​

    public class Timestamp

    {

        public DateTime gte { get; set; }

        public DateTime lt { get; set; }

    }

​

    public class Range

    {

        [JsonProperty("@timestamp")]

        public Timestamp Timestamp { get; set; }

    }

​

    public class Filter

    {

        public Range range { get; set; }

    }

​

    public class Bool

    {

        public List<Should> should { get; set; }

        public List<Filter> filter { get; set; }

        public int minimum_should_match { get; set; }

    }

​

    public class Query

    {

        public Bool @bool { get; set; }

    }

​

    public class Root

    {

        public Root() 

        {

            size = 1000;

            query = new();

            query.@bool = new();

            query.@bool.should = new();

            // skipping the rest ...

        }

        public int size { get; set; }

        public Query query { get; set; }

    }

​

​

// Root myDeserializedClass = JsonConvert.DeserializeObject<Root>(myJsonResponse); 

    public class IDField

    {

        public string FieldName { get; set; }

    }

​

    public class FieldValue

    {

        public string value { get; set; }

    }

​

    public class LevelField

    {

        public string FieldName { get; set; }

        public List<FieldValue> FieldValue { get; set; }

    }

​

    public class LogFieldsMapping

    {

        public IDField IDField { get; set; }

        public LevelField LevelField { get; set; }

    }

​

    public class Root2

    {

        public LogFieldsMapping LogFieldsMapping { get; set; }

    }

​

​