# IRhinoDocObserver interface

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

```cs
public interface IRhinoDocObserver
```

Implement this interface if you are a modeless interface to aid in handling multiple document implementations

## Methods

- [ActiveRhinoDocChanged](https://developer.rhino3d.com/api/rhinocommon/type/rhino.irhinodocobserver/activerhinodocchanged.md): In Windows Rhino this will mean a new document has been created or opened. In Mac Rhino this can mean the same thing as well it can indicate switching from one active open document to another.
- [RhinoDocClosed](https://developer.rhino3d.com/api/rhinocommon/type/rhino.irhinodocobserver/rhinodocclosed.md): When a document is closed