# IGH_InstanceGuidDependent interface

Namespace: [Grasshopper.Kernel](https://developer.rhino3d.com/api/gh1/namespace/grasshopper.kernel.md) · Assembly: [Grasshopper](https://developer.rhino3d.com/api/gh1/assembly/grasshopper.md)

```cs
public interface IGH_InstanceGuidDependent
```

Implement this interface in your IGH_DocumentObject class if you want to be informed when the InstanceGuids of objects in the document are mutated.

**Derived types:** [GH_Cluster](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.special.gh-cluster.md), [GH_Group](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.special.gh-group.md), [GH_Timer](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.special.gh-timer.md)

## Methods

- [InstanceGuidsChanged](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-instanceguiddependent/instanceguidschanged.md): This method will be called by the GH_Document that owns this object after it mutates some or all of it's object InstanceIds.