using System;

using System.Collections.Generic;

using System.Collections;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        const string json =@"

        {

           ""name"":""Object Name"",

           ""attributes"":{

              ""key1"":""adfadfd"",

              ""key1"":""adfadfadf""

           }

        }

        ";

        Console.WriteLine(JsonConvert.DeserializeObject<Model>(json));

    }

    public class Model

    {

        public string Name { get; set; }

        public StrictDictionary<string, string> Attributes { get; set; }

    }

    public class StrictDictionary<TKey, TValue> : IDictionary<TKey, TValue>

    {

        public Dictionary<TKey, TValue> InnerDictionary {get; set; } = new Dictionary<TKey, TValue>();

        public bool ContainsKey(TKey key) => InnerDictionary.ContainsKey(key);

        public void Add(TKey key, TValue value) => InnerDictionary.Add(key, value);

        void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> kvp) => ((ICollection<KeyValuePair<TKey, TValue>>) InnerDictionary).Add(kvp);

        bool ICollection<KeyValuePair<TKey, TValue>>.Contains(KeyValuePair<TKey, TValue> kvp) => ((ICollection<KeyValuePair<TKey, TValue>>) InnerDictionary).Contains(kvp);

        void ICollection<KeyValuePair<TKey, TValue>>.CopyTo(KeyValuePair<TKey, TValue>[] array, int i) => ((ICollection<KeyValuePair<TKey, TValue>>) InnerDictionary).CopyTo(array, i);

        public void Clear() => InnerDictionary.Clear();

        public bool Remove(TKey key) => InnerDictionary.Remove(key);

        bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> kvp) => ((ICollection<KeyValuePair<TKey, TValue>>) InnerDictionary).Remove(kvp);

        public bool TryGetValue(TKey key, out TValue value) => InnerDictionary.TryGetValue(key, out value);

        public ICollection<TKey> Keys => InnerDictionary.Keys;

        public ICollection<TValue> Values => InnerDictionary.Values;

        public int Count => InnerDictionary.Count;

        public bool IsReadOnly => ((ICollection<KeyValuePair<TKey, TValue>>) InnerDictionary).IsReadOnly;

        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() => InnerDictionary.GetEnumerator();

        IEnumerator IEnumerable.GetEnumerator() => InnerDictionary.GetEnumerator();

​

        public TValue this[TKey key]

        {

            get => InnerDictionary[key];

            set => InnerDictionary.Add(key, value);

        }

    }

}