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# DockAccessory.StateChange

An event that indicates a change in the state of a dock accessory.

```
struct StateChange
```

## Overview

DockKit generates this event when a device docks or undocks from the dock accessory, or when a person presses the tracking button.
To iterate the stream of state changes, see [`accessoryStateChanges`](/documentation/DockKit/DockAccessoryManager/accessoryStateChanges).

## Topics

### Getting properties

[`accessory`](/documentation/DockKit/DockAccessory/StateChange/accessory)

The dock accessory that generated the event.

[`state`](/documentation/DockKit/DockAccessory/StateChange/state)

The state of the dock accessory associated with the event.


---

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