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# NSCollectionView.DropOperation

These constants specify if acceptance of a drop should be at the item it is dropped on or before the item. These constants are used by the  [`collectionView(_:acceptDrop:index:dropOperation:)`](/documentation/AppKit/NSCollectionViewDelegate/collectionView(_:acceptDrop:index:dropOperation:)) and [`collectionView(_:validateDrop:proposedIndex:dropOperation:)`](/documentation/AppKit/NSCollectionViewDelegate/collectionView(_:validateDrop:proposedIndex:dropOperation:)) methods in [`NSCollectionViewDelegate`](/documentation/AppKit/NSCollectionViewDelegate)

```
enum DropOperation
```

## Topics

### Constants

[`NSCollectionViewDropOn`](/documentation/AppKit/NSCollectionView/DropOperation/on)

The drop occurs at the collection view item to which the item was dragged.

[`NSCollectionViewDropBefore`](/documentation/AppKit/NSCollectionView/DropOperation/before)

The drop occurs before the collection view item to which the item was dragged.

## Relationships

### Conforms To

[`Hashable`](/documentation/Swift/Hashable)

[`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable)

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

[`Sendable`](/documentation/Swift/Sendable)

[`Equatable`](/documentation/Swift/Equatable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

---

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