# GH_ExpressionUndoAction class

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

```cs
public class GH_ExpressionUndoAction : GH_ObjectUndoAction
```

Undo action for expression changes in a parameter.

## Constructors

- [GH_ExpressionUndoAction](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.parameters.gh-expressionundoaction/ctor.md)

## Properties

- [ExpiresSolution](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.parameters.gh-expressionundoaction/expiressolution.md)

## Methods

- [Object_Redo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.parameters.gh-expressionundoaction/object-redo.md)
- [Object_Undo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.parameters.gh-expressionundoaction/object-undo.md)

## Inherited Members

- From [GH_ObjectUndoAction](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-objectundoaction.md): [Internal_Redo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-objectundoaction/internal-redo.md), [Internal_Undo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-objectundoaction/internal-undo.md)
- From [GH_UndoAction](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction.md): [ExpiresDisplay](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/expiresdisplay.md), [State](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/state.md), [Read](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/read.md), [Redo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/redo.md), [Undo](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/undo.md), [Write](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.undo.gh-undoaction/write.md)