SerializationUtility.GetManagedReference

Description

Retrieves an object based on its managed reference Id.

This method makes it possible to retrieve a specific referenced object efficiently, for example when its current location inside an array or graph of references isn't known. This method returns null when the Id isn't assigned to any object. Additional resources: GetManagedReferenceIdForObject, SerializeReference.

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

public class GetManagedReferenceExample : ScriptableObject
{
    [Serializable]
    public class Item
    {
        public char m_data;
    }

    [SerializeReference]
    public List<Item> m_items = new List<Item>();

    private void InsertNewItem(long id, char data)
    {
        var newItem = new Item() {m_data = data};
        if (SerializationUtility.SetManagedReferenceIdForObject(this, newItem, id))
            m_items.Add(newItem);
    }

    [MenuItem("Example/SerializationUtility GetManagedReference Example")]
    static void TestMethod()
    {
        var scriptableObject = ScriptableObject.CreateInstance<GetManagedReferenceExample>();

        scriptableObject.InsertNewItem(1000, 'a');
        scriptableObject.InsertNewItem(1001, 'b');
        scriptableObject.InsertNewItem(1002, 'c');
        scriptableObject.InsertNewItem(1003, 'd');

        // Because 1002 is registered in an earlier call this will log an error and not change the state
        scriptableObject.InsertNewItem(1002, 'e');

        // The array may get reordered over time.  One way to find an specific item again would
        // be to look it up based on a known managed reference id
        var item = SerializationUtility.GetManagedReference(scriptableObject, 1002) as Item;
        Debug.LogFormat("Data on object 1002 is {0}", item.m_data);

        var willBeNull = SerializationUtility.GetManagedReference(scriptableObject, 9999) as Item;
    }
}