C# Newtonsoft json serialization Dictionary<int, int> get saved as <string, int>

Question

I'm trying to load some saved json string and turn it into a <int, int> dictionary, then add some items and then turn it back into a string. But for some reason the key gets saved as a string, not int.

I'm using the following code:

using Newtonsoft.Json;

var dictionary = JsonConvert.DeserializeObject<Dictionary<int, int>>("{}");
dictionary[1] = 1;
string updatedDictionary = JsonConvert.SerializeObject(dictionary);
Debug.Log(updatedDictionary); // {"1":1}
Debug.Log(updatedDictionary[1]); // "

but the updatedDictionary is printed as {"1":1} ... why is that? And how can I fix this? I cannot event just convert to string when looking up the dictionary because it only allows int look ups. So I really need to make sure that the json is saved as int int key value pair, and not turn into string keys.

The same happens when I do dictionary.Add(1, 1) So I'm pretty sure the problem lies in the SerializeObject call.

Answer 1

Json Object must use strings for their keys.

https://www.w3schools.com/js/js_json_objects.asp#:~:text=Object%20Syntax&text=JSON%20objects%20are%20written%20in,are%20separated%20by%20a%20colon .