# ClassIdAttribute class

Namespace: [Rhino.DocObjects.Custom](https://developer.rhino3d.com/api/rhinocommon/namespace/rhino.docobjects.custom.md) · Assembly: [RhinoCommon](https://developer.rhino3d.com/api/rhinocommon/assembly/rhinocommon.md)

```cs
[AttributeUsage(AttributeTargets.Class)]
public sealed class ClassIdAttribute : Attribute
```

Useful for legacy UserData

## Constructors

- [ClassIdAttribute](https://developer.rhino3d.com/api/rhinocommon/type/rhino.docobjects.custom.classidattribute/ctor.md): Initializes a class id attribute.

## Properties

- [Id](https://developer.rhino3d.com/api/rhinocommon/type/rhino.docobjects.custom.classidattribute/id.md): Gets the associated style.