Unity JsonUtility SerializableSortedList

SerializableSortedList.cs

[Serializable]
public class SerializableSortedList<TKey, TValue> : SortedList<TKey, TValue>, ISerializationCallbackReceiver
{
    [SerializeField] private List<TKey> keys = new List<TKey>();
    [SerializeField] private List<TValue> values = new List<TValue>();

    // Unity serialization callback before serialization
    public void OnBeforeSerialize()
    {
        keys.Clear();
        values.Clear();

        foreach (var kvp in this)
        {
            keys.Add(kvp.Key);
            values.Add(kvp.Value);
        }
    }

    // Unity serialization callback after deserialization
    public void OnAfterDeserialize()
    {
        this.Clear();

        if (keys.Count != values.Count)
        {
            throw new Exception("The number of keys and values in the SortedList do not match.");
        }

        for (int i = 0; i < keys.Count; i++)
        {
            this[keys[i]] = values[i];
        }
    }
}