# itemExpandedChanged

> Raised when an item is expanded or collapsed.

## Definition

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

```csharp
public event Action<TreeViewExpansionChangedArgs> itemExpandedChanged
```

### Remarks

The [TreeViewExpansionChangedArgs](/engine/6000.3/script-reference/unityengine/uielements/treeviewexpansionchangedargs.md) will contain the expanded state of the item being modified.