SerializableDictionary.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

//
// Unity doesn't know how to serialize a Dictionary
// So this is a simple extension of a dictionary that saves as two lists.
// By Pablo Bollansée

//
// Usage is a little strange though, for some reason you can't use it directly in unity.
// You have to make a non-generic instance of it, and then use it. This is luckily quite easy:
// 
// [System.Serializable]
// class MyDictionary : SerializableDictionary<KeyType, ValueType> {}
//
// Then make an instance of this like this:
//
// [SerializeField]
// private MyDictionary _dictionary = new MyDictionary();
//
// Now you can use it in exactly the same way as a notmal Dictionary. Everything just works.

[System.Serializable]
public class SerializableDictionary<TKey,TValue> : 
	Dictionary<TKey, TValue>, ISerializationCallbackReceiver {
	
	// We save the keys and values in two lists because Unity does understand those.
	[SerializeField, HideInInspector]
	private List<TKey> _keys;
	[SerializeField, HideInInspector]
	private List<TValue> _values;
	
	// Before the serialization we fill these lists
	public void OnBeforeSerialize() {
		_keys = new List<TKey>(this.Count);
		_values = new List<TValue>(this.Count);
		foreach(var kvp in this) {
			_keys.Add(kvp.Key);
			_values.Add(kvp.Value);
		}
	}
	
	// After the serialization we create the dictionary from the two lists
	public void OnAfterDeserialize() {
		this.Clear();
		for (int i=0; i!= Mathf.Min(_keys.Count,_values.Count); i++) {
			this.Add(_keys[i],_values[i]);
		}
	}
}