---
title: "outlineView(_:shouldReorderColumn:toColumn:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nsoutlineviewdelegate/outlineview(_:shouldreordercolumn:tocolumn:)"
---

# outlineView(_:shouldReorderColumn:toColumn:)

Sent to the delegate to allow or prohibit the specified column to be dragged to a new location.

## Declaration

```swift
@MainActor optional func outlineView(_ outlineView: NSOutlineView, shouldReorderColumn columnIndex: Int, toColumn newColumnIndex: Int) -> Bool
```

## Parameters

- `outlineView`: The outline view that sent the message.
- `columnIndex`: The index of the column being dragged.
- `newColumnIndex`: The proposed target index of the column.

## Return Value

Return Value true if the column reordering should be allowed, otherwise false.

## Discussion

Discussion When a column is initially dragged by the user, the delegate is first called with a newColumnIndex value of -1. Returning false will disallow that column from being reordered at all. Returning true allows it to be reordered, and the delegate will be called again when the column reaches a new location. The actual NSTableColumn instance can be retrieved from the tableColumns array. If this method is not implemented, all columns are considered reorderable.