---
title: "trackKnob(with:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nsscroller/trackknob(with:)"
---

# trackKnob(with:)

Tracks the knob and sends action messages to the receiver’s target.

## Declaration

```swift
func trackKnob(with event: NSEvent)
```

## Discussion

Discussion This method is invoked automatically when the receiver receives theEvent mouse-down event in the knob; you should not invoke it directly.

## See Also

### Event Handling

- [hitPart](appkit/nsscroller/hitpart.md)
- [trackScrollButtons(with:)](appkit/nsscroller/trackscrollbuttons(with:).md)