# UnknownVariableException class

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

```cs
public class UnknownVariableException : Exception
```

Thrown when an unrecognised variable name is used.

## Constructors

- [UnknownVariableException](https://developer.rhino3d.com/api/gh2/type/grasshopper2.expressions.unknownvariableexception/ctor.md): Create a new UnknownVariableException.