using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

using Newtonsoft.Json.Converters;

public class Program

{

    public static void Main()

    {

        var json = "{\"childrenOp\": \"and\", \"children\": [{\"value\": \"text\",\"importance\": 100},{\"childrenOp\": \"or\",\"children\": [{\"value\": \"text2\",\"importance\": 100},{\"value\": \"text3\",\"importance\": 100},{\"childrenOp\": \"and\",\"children\": [{\"value\": \"text4\",\"importance\": 100}]}]}]}";

        var model = JsonConvert.DeserializeObject<ElementModel>(json);

        Console.WriteLine(JsonConvert.SerializeObject(model, Formatting.Indented));

    }

}

​

public class ElementModel

{

    /// <summary>

    ///     The operator between the <see cref="Children" />. When set <see cref="Value" /> and <see cref="Importance" /> is null.

    /// </summary>

    [JsonConverter(typeof(StringEnumConverter))]

    public Operator? ChildrenOp { get; set; }

​

    /// <summary>

    ///     The child elements. Used together with <see cref="ChildrenOp" />. When set <see cref="Value" /> and <see cref="Importance" /> is null.

    /// </summary>

    public List<ElementModel> Children { get; set; }

​

    /// <summary>

    ///     The value of the element. Used together with <see cref="Importance" />, null if <see cref="Children" /> is set.

    /// </summary>

    public string Value { get; set; }

​

    /// <summary>

    ///     The importance of the element. Used together with <see cref="Value" />, null if <see cref="Children" /> is set.

    /// </summary>

    public int? Importance { get; set; }

​

    public ElementModel()

    {

    }

​

    public ElementModel(string value, int importance)

    {

        Value      = value;

        Importance = importance;

    }

​

    public ElementModel(Operator childrenOp, params ElementModel[] children)

    {

        ChildrenOp = childrenOp;

        Children   = children.ToList();

    }

}

​

public enum Operator

{

    and,

    or

}