# browser(_:validateDrop:proposedRow:column:dropOperation:) Sent to the delegate during a dragging session to determine whether a drop should be accepted and to obtain the drop location. This method is required for a browser to be a drag destination. ``` @MainActor optional func browser(_ browser: NSBrowser, validateDrop info: any NSDraggingInfo, proposedRow row: UnsafeMutablePointer, column: UnsafeMutablePointer, dropOperation: UnsafeMutablePointer) -> NSDragOperation ``` ## Parameters `browser` The browser. `info` The drag session information. `row` On input, the proposed drop row. On output, the drop row. `column` On input, the proposed drop column. On output, the drop column. `dropOperation` On input, the proposed drop location. On output, the drop location. ## Return Value The drag operation that the data source is to perform. For the browser to accept the drop, it must not be [`NSDragOperationNone`](/documentation/AppKit/NSDragOperation/NSDragOperationNone). ## Discussion The browser proposes a drop column, row, and row-relative location for the drop based on the pointer position, as shown in this table: |Drop relative location |Description | |-----------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| |``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/on`` |Dragging location (`dragInfo``.draggingLocation`) is closer to the middle of `row` than to either of its vertical sides.| |``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/above``|Dragging location is between two rows. Indicates a drop location above `row` and below `row` `- 1`. | These are a few examples of how to specify a drop location: | |Row index |Row-relative location | |--------------------|-----------------------|-----------------------------------------------------------------------------| |On row 2 |`2` |``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/on`` | |Between rows 2 and 3|`3` |``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/above``| |Below the last row |`[sender numberOfRows]`|``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/above``| |All rows |`-1` |``doc://com.apple.appkit/documentation/AppKit/NSBrowser/DropOperation/on`` | ## See Also [`registerForDraggedTypes(_:)`](/documentation/AppKit/NSView/registerForDraggedTypes(_:)) Registers the pasteboard types that the view will accept as the destination of an image-dragging session. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)