# LifecycleAttributeBase

> Base class for lifecycle callback attributes.

## Definition

* **Type:** Class
* **Namespace:** [Unity.Scripting.LifecycleManagement](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement.md)
* **Assembly:** Unity.Scripting
* **Inherits from:** [RequiredMemberAttribute](/engine/6000.6/script-reference/unityengine/scripting/requiredmemberattribute.md)

```csharp
public abstract class LifecycleAttributeBase : RequiredMemberAttribute
```

## Remarks

This is the abstract base class for all lifecycle callback attributes. Do not inherit from this class directly; use the specific lifecycle attributes instead:

* [OnCodeLoadedAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeloadedattribute.md) / [OnCodeUnloadingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeunloadingattribute.md) - Code loading lifecycle.
* [OnCodeInitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeinitializingattribute.md) / [OnCodeDeinitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodedeinitializingattribute.md) - Object serialization lifecycle.

**Lifecycle Timing:**

Code reload order (Editor only):

1. [OnCodeDeinitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodedeinitializingattribute.md) - Objects serialized.
2. [OnCodeUnloadingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeunloadingattribute.md) - Code about to unload.
3. (Code unloads and reloads)
4. [OnCodeLoadedAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeloadedattribute.md) - Code loaded.
5. [OnCodeInitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeinitializingattribute.md) - Objects deserialized.

Initial code load (Editor and Player):

1. [OnCodeLoadedAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeloadedattribute.md) - Code loaded.
2. [OnCodeInitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeinitializingattribute.md) - Called before initial scene loads.

Shutdown (Editor and Player):

1. [OnCodeUnloadingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeunloadingattribute.md) - Code about to unload.

Additional Resources: [OnCodeLoadedAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeloadedattribute.md), [OnCodeInitializingAttribute](/engine/6000.6/script-reference/unity/scripting/lifecyclemanagement/oncodeinitializingattribute.md).

## 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)