---
title: "outlineViewSelectionIsChanging(_:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nsoutlineviewdelegate/outlineviewselectionischanging(_:)"
---

# outlineViewSelectionIsChanging(_:)

Invoked when notification is posted—that is, whenever the outline view’s selection changes.

## Declaration

```swift
@MainActor optional func outlineViewSelectionIsChanging(_ notification: Notification)
```

## Parameters

- `notification`: The posted notification.

## Discussion

Discussion This method is invoked as a result of posting an selectionIsChangingNotification.

## See Also

### Handling Selection

- [outlineView(_:shouldSelect:)](appkit/nsoutlineviewdelegate/outlineview(_:shouldselect:).md)
- [outlineView(_:shouldSelectItem:)](appkit/nsoutlineviewdelegate/outlineview(_:shouldselectitem:).md)
- [outlineView(_:selectionIndexesForProposedSelection:)](appkit/nsoutlineviewdelegate/outlineview(_:selectionindexesforproposedselection:).md)
- [selectionShouldChange(in:)](appkit/nsoutlineviewdelegate/selectionshouldchange(in:).md)
- [outlineViewSelectionDidChange(_:)](appkit/nsoutlineviewdelegate/outlineviewselectiondidchange(_:).md)