---
title: willReorderHandler
framework: uikit
role: symbol
role_heading: Instance Property
path: uikit/uicollectionviewdiffabledatasourcereorderinghandlers/willreorderhandler
---

# willReorderHandler

The handler that prepares the diffable data source for reordering its items.

## Declaration

```occ
@property (nonatomic, copy, nullable) void (^willReorderHandler)(NSDiffableDataSourceTransaction<id,id> *);
```

## See Also

### Reordering items

- [canReorderItemHandler](uikit/uicollectionviewdiffabledatasourcereorderinghandlers/canreorderitemhandler.md)
- [didReorderHandler](uikit/uicollectionviewdiffabledatasourcereorderinghandlers/didreorderhandler.md)