# FormerlySerializedAsAttribute

> Use this attribute to rename a field without losing its serialized value.

## Definition

* **Type:** Class
* **Namespace:** [UnityEngine.Serialization](/engine/6000.0/script-reference/unityengine/serialization.md)
* **Assembly:** UnityEngine.CoreModule
* **Inherits from:** [Attribute](https://learn.microsoft.com/dotnet/api/system.attribute)
* **Implements:** [\_Attribute](https://learn.microsoft.com/dotnet/api/system.runtime.interopservices._attribute)

```csharp
[AttributeUsage(AttributeTargets.Field, AllowMultiple = true, Inherited = false)]
public class FormerlySerializedAsAttribute : Attribute, _Attribute
```

## Remarks

Suppose you have a class like this:

```csharp
using UnityEngine;

public class MyMonster : MonoBehaviour
{
    public int hitpoints;
}
```

And you would now like to rename this field. You can achieve that by using this attribute:

```csharp
using UnityEngine;
using UnityEngine.Serialization;

public class MyMonster : MonoBehaviour
{
    [FormerlySerializedAs("hitpoints")]
    public int health;
}
```

Unity serializes public variables by default. To serialize private variables, use the SerializeField attribute. For more information, see the [Script Serialization documentation](/engine/6000.0/manual/scripting/compilation-and-code-reload/script-serialization.md).

## Properties

| Property                                                                                                      | Description                              |
| ------------------------------------------------------------------------------------------------------------- | ---------------------------------------- |
| [oldName](/engine/6000.0/script-reference/unityengine/serialization/formerlyserializedasattribute/oldname.md) | The name of the field before the rename. |

## Inheritance

**Inherited Members:**

* [Attribute.GetCustomAttributes(MemberInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-memberinfo-system-type\))
* [Attribute.GetCustomAttributes(MemberInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-memberinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(MemberInfo)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-memberinfo\))
* [Attribute.GetCustomAttributes(MemberInfo, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-memberinfo-system-boolean\))
* [Attribute.IsDefined(MemberInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-memberinfo-system-type\))
* [Attribute.IsDefined(MemberInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-memberinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttribute(MemberInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-memberinfo-system-type\))
* [Attribute.GetCustomAttribute(MemberInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-memberinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(ParameterInfo)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-parameterinfo\))
* [Attribute.GetCustomAttributes(ParameterInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-parameterinfo-system-type\))
* [Attribute.GetCustomAttributes(ParameterInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-parameterinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(ParameterInfo, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-parameterinfo-system-boolean\))
* [Attribute.IsDefined(ParameterInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-parameterinfo-system-type\))
* [Attribute.IsDefined(ParameterInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-parameterinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttribute(ParameterInfo, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-parameterinfo-system-type\))
* [Attribute.GetCustomAttribute(ParameterInfo, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-parameterinfo-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(Module, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-module-system-type\))
* [Attribute.GetCustomAttributes(Module)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-module\))
* [Attribute.GetCustomAttributes(Module, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-module-system-boolean\))
* [Attribute.GetCustomAttributes(Module, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-module-system-type-system-boolean\))
* [Attribute.IsDefined(Module, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-module-system-type\))
* [Attribute.IsDefined(Module, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-module-system-type-system-boolean\))
* [Attribute.GetCustomAttribute(Module, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-module-system-type\))
* [Attribute.GetCustomAttribute(Module, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-module-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(Assembly, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-assembly-system-type\))
* [Attribute.GetCustomAttributes(Assembly, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-assembly-system-type-system-boolean\))
* [Attribute.GetCustomAttributes(Assembly)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-assembly\))
* [Attribute.GetCustomAttributes(Assembly, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattributes#system-attribute-getcustomattributes\(system-reflection-assembly-system-boolean\))
* [Attribute.IsDefined(Assembly, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-assembly-system-type\))
* [Attribute.IsDefined(Assembly, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.isdefined#system-attribute-isdefined\(system-reflection-assembly-system-type-system-boolean\))
* [Attribute.GetCustomAttribute(Assembly, Type)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-assembly-system-type\))
* [Attribute.GetCustomAttribute(Assembly, Type, bool)](https://learn.microsoft.com/dotnet/api/system.attribute.getcustomattribute#system-attribute-getcustomattribute\(system-reflection-assembly-system-type-system-boolean\))
* [Attribute.Equals(Object)](https://learn.microsoft.com/dotnet/api/system.attribute.equals)
* [Attribute.GetHashCode()](https://learn.microsoft.com/dotnet/api/system.attribute.gethashcode)
* [Attribute.Match(Object)](https://learn.microsoft.com/dotnet/api/system.attribute.match)
* [Attribute.IsDefaultAttribute()](https://learn.microsoft.com/dotnet/api/system.attribute.isdefaultattribute)
* [Attribute.TypeId()](https://learn.microsoft.com/dotnet/api/system.attribute.typeid)