# IGH_VarParamComponent 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
[EditorBrowsable(EditorBrowsableState.Never)]
public interface IGH_VarParamComponent
```

This interface is obsolete, please use the IGH_VariableParameterComponent interface instead.

**Derived types:** [GH_ExplodeTreeComponent_OBSOLETE](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.components.gh-explodetreecomponent-obsolete.md), [GH_StreamFilterComponent_OBSOLETE](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.components.gh-streamfiltercomponent-obsolete.md), [GH_StreamGateComponent_OBSOLETE](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.components.gh-streamgatecomponent-obsolete.md)

## Properties

- [IsInputVariable](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/isinputvariable.md): Gets a flag specifying whether or not the input can potentially contain variable parameters.
- [IsOutputVariable](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/isoutputvariable.md): Gets a flag specifying whether or not the output can potentially contain variable parameters.

## Methods

- [ConstructVariable](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/constructvariable.md): This function is called whenever a new parameter is required. You must provide a non-null instance for new_param, otherwise the addition will be cancelled. The Param field of the event arguments will typically be null.
- [IsVariableParam](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/isvariableparam.md): Returns a value indicating whether a specific parameter is considered to be variable.
- [ManagerConstructed](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/managerconstructed.md): This function is called whenever a new manager is constructed. You can override this function if you wish to modify the default behaviour of the manager.
- [ParametersModified](https://developer.rhino3d.com/api/gh1/type/grasshopper.kernel.igh-varparamcomponent/parametersmodified.md): This function will be called wheneven the param collection of a component has been altered through the ParamManager. If your parameters have a peculiar naming scheme, this is the best place to assign those.