# allowAdd

> This property allows the user to allow or block the addition of an item when clicking on the Add Button. It must return true or false.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.UIElements](/engine/6000.3/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule

```csharp
public bool allowAdd { get; set; }
```

### Remarks

If the callback is not set to `false`, any Add operation will be allowed.