---
title: noteNumberOfItemsChanged()
framework: appkit
role: symbol
role_heading: Instance Method
path: appkit/nscombobox/notenumberofitemschanged()
---

# noteNumberOfItemsChanged()

Informs the receiver that the number of items in its data source has changed.

## Declaration

```swift
func noteNumberOfItemsChanged()
```

## Discussion

Discussion This method allows the receiver to update the scrollers in its displayed pop-up list without actually reloading data into the receiver. It is particularly useful for a data source that continually receives data in the background over a period of time, in which case the NSComboBox can remain responsive to the user while the data is received. See the NSComboBoxDataSource informal protocol specification for information on the messages an NSComboBox sends to its data source.

## See Also

### Manipulating the Displayed List

- [indexOfItem(withObjectValue:)](appkit/nscombobox/indexofitem(withobjectvalue:).md)
- [itemObjectValue(at:)](appkit/nscombobox/itemobjectvalue(at:).md)
- [reloadData()](appkit/nscombobox/reloaddata().md)
- [scrollItemAtIndexToTop(_:)](appkit/nscombobox/scrollitematindextotop(_:).md)
- [scrollItemAtIndexToVisible(_:)](appkit/nscombobox/scrollitematindextovisible(_:).md)