---
title: "invalidateItems(at:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nscollectionviewlayoutinvalidationcontext/invalidateitems(at:)"
---

# invalidateItems(at:)

Marks the specified items as invalid so that their layout information can be updated.

## Declaration

```swift
func invalidateItems(at indexPaths: Set<IndexPath>)
```

## Parameters

- `indexPaths`: A set of doc://com.apple.documentation/documentation/Foundation/NSIndexPath objects. Each index path represents an item whose layout needs to be recomputed.

## Discussion

Discussion Call this method when you want the layout object to recompute attributes for a specific set of items. The items you provide are added to the invalidatedItemIndexPaths property. You can call this method more than once to create a merged set of items.

## See Also

### Invalidating Specific Items

- [invalidateSupplementaryElements(ofKind:at:)](appkit/nscollectionviewlayoutinvalidationcontext/invalidatesupplementaryelements(ofkind:at:).md)
- [invalidateDecorationElements(ofKind:at:)](appkit/nscollectionviewlayoutinvalidationcontext/invalidatedecorationelements(ofkind:at:).md)
- [invalidatedItemIndexPaths](appkit/nscollectionviewlayoutinvalidationcontext/invalidateditemindexpaths.md)
- [invalidatedSupplementaryIndexPaths](appkit/nscollectionviewlayoutinvalidationcontext/invalidatedsupplementaryindexpaths.md)
- [invalidatedDecorationIndexPaths](appkit/nscollectionviewlayoutinvalidationcontext/invalidateddecorationindexpaths.md)