# FilterFunction

> Represents a filter function that holds the definition and parameters of a filter.

## Definition

* **Type:** Struct
* **Namespace:** [UnityEngine.UIElements](/engine/6000.6/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule
* **Implements:** [IEquatable\<FilterFunction>](https://learn.microsoft.com/dotnet/api/system.iequatable-1)

```csharp
public struct FilterFunction : IEquatable<FilterFunction>
```

## Constructors

| Constructor                                                                                                                                                                                 | Description                                                                                                                                                                 |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [FilterFunction(UnityEngine.UIElements.FilterFunctionDefinition)](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/ctor.md#filterfunction\(filterfunctiondefinition\)) | Initializes a new custom filter function with the specified [FilterFunctionDefinition](/engine/6000.6/script-reference/unityengine/uielements/filterfunctiondefinition.md). |
| [FilterFunction(UnityEngine.UIElements.FilterFunctionType)](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/ctor.md#filterfunction\(filterfunctiontype\))             | Initializes a new filter function with the specified [FilterFunctionType](/engine/6000.6/script-reference/unityengine/uielements/filterfunctiontype.md).                    |

## Properties

| Property                                                                                                      | Description                                                                                                                                                                               |
| ------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [customDefinition](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/customdefinition.md) | The custom filter function definition, when the filter function type is [FilterFunctionType.Custom](/engine/6000.6/script-reference/unityengine/uielements/filterfunctiontype/custom.md). |
| [parameterCount](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/parametercount.md)     | The number of parameters in the filter function.                                                                                                                                          |
| [type](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/type.md)                         | The type of the filter function.                                                                                                                                                          |

## Methods

| Method                                                                                                      | Description                                                    |
| ----------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------- |
| [AddParameter](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/addparameter.md)       | Adds a parameter to the filter function.                       |
| [ClearParameters](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/clearparameters.md) | Clears all parameters from the filter function.                |
| [GetParameter](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/getparameter.md)       | Gets the parameter at the specified index.                     |
| [SetParameter](/engine/6000.6/script-reference/unityengine/uielements/filterfunction/setparameter.md)       | Sets a parameter to the filter function at the provided index. |