---
title: Outline View Button Keys
framework: appkit
role: collectionGroup
role_heading: API Collection
path: appkit/outline-view-button-keys
---

# Outline View Button Keys

These keys are used by the outline view to create disclosure buttons that collapse and expand items.

## Overview

Overview The outline view creates these buttons by calling its inherited makeView(withIdentifier:owner:) method, passing in the key as the identifier and the delegate as the owner. note: These keys are backwards compatible to OS X v10.7, however, the symbol is not exported prior to v10.9 and the string value (@"NSOutlineViewDisclosureButtonKey") must be used.

## Topics

### Constants

- [disclosureButtonIdentifier](appkit/nsoutlineview/disclosurebuttonidentifier.md)
- [showHideButtonIdentifier](appkit/nsoutlineview/showhidebuttonidentifier.md)

## See Also

### Constants

- [Drop on Item Index](appkit/drop-on-item-index.md)