Serializers in Unity are specifically designed to operate efficiently at runtime. Because of this, serialization in Unity behaves differently to serialization in other programming environments. Serializers in Unity work directly on the fields of your C# classes rather than their properties, so Unity only serializes your fields if they meet certain conditions. The following section outlines how to use field serialization in Unity.
To use field serialization you must ensure that the field:
public
, or has a SerializeField attribute
private
fields are serialized, refer to Hot reloading
static
const
readonly
List<T>
of a field type mentioned aboveNote: Unity doesn’t support serialization of multilevel types (multidimensional arrays, jagged arrays, dictionaries, and nested container types). If you want to serialize these, you have two options:
For Unity to serialize a custom class, you must ensure the class:
When you assign an instance of a UnityEngine.Object
-derived class to a field and Unity saves that field, Unity serializes the field as a reference to that instance. Unity serializes the instance itself independently, so it isn’t duplicated when multiple fields are assigned to the instance. But for custom classes which don’t derive from UnityEngine.Object
, Unity includes the state of the instance directly in the serialized data of the MonoBehaviour or ScriptableObject that references them. There are two ways that this can happen: inline and by [SerializeReference]
.
[SerializeReference]
on the field that references the class. This means that if you store a reference to an instance of a custom class in several different fields, they become separate objects when serialized. Then, when Unity deserializes the fields, they contain different distinct objects with identical data.[SerializeReference]
serialization: If you do specify [SerializeReference]
, Unity establishes the object as a managed reference. The host object still stores the objects directly in its serialized data, but in a dedicated registry section.
[SerializeReference]
adds some overhead but supports the following cases:
[SerializeReference]
, then they become separate objects when serialized.[SerializeReference]
Unity only serializes the fields that belong to the parent class. When Unity deserializes the class instance, it instantiates the parent class instead of the derived class.
Note: Inline serialization is more efficient, and you should use it unless you specifically need one of the features that [SerializeReference]
supports. For full details on how to use [SerializeReference]
, refer to the SerializeReference documentation.
Unity doesn’t normally serialize properties except in the following situations:
public int MyInt
{
get => m_backing;
private set => m_backing = value;
}
[SerializeField] private int m_backing;
public int MyInt { get; set; }
If you don’t want Unity to serialize a property with auto-generated fields, use the [field: NonSerialized]
attribute.