# BeforeAfterEventArgs<TOwner, TData> class

Namespace: [Grasshopper2](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public class BeforeAfterEventArgs<TOwner, TData> : EventArgs
```

Utility event arguments for events that provide both before and after values.

**Type parameters:**

- `TOwner`: Type of class which raised the event.
- `TData`: Type of data changed.

**Derived types:** [GradientEventArgs](https://developer.rhino3d.com/api/gh2/type/grasshopper2.ui.gradient.gradienteventargs.md), [ObjectNameEventArgs](https://developer.rhino3d.com/api/gh2/type/grasshopper2.doc.objectnameeventargs.md)

## Constructors

- [BeforeAfterEventArgs<TOwner, TData>](https://developer.rhino3d.com/api/gh2/type/grasshopper2.beforeaftereventargs-2/ctor.md): Construct a new instance.

## Properties

- [New](https://developer.rhino3d.com/api/gh2/type/grasshopper2.beforeaftereventargs-2/new.md): Gets the new value.
- [Old](https://developer.rhino3d.com/api/gh2/type/grasshopper2.beforeaftereventargs-2/old.md): Gets the old value.
- [Owner](https://developer.rhino3d.com/api/gh2/type/grasshopper2.beforeaftereventargs-2/owner.md): Gets the source for this event.