---
title: "tableView(_:heightOfRow:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nstableviewdelegate/tableview(_:heightofrow:)"
---

# tableView(_:heightOfRow:)

Asks the delegate for the height of the specified row.

## Declaration

```swift
@MainActor optional func tableView(_ tableView: NSTableView, heightOfRow row: Int) -> CGFloat
```

## Parameters

- `tableView`: The table view that sent the message.
- `row`: The row index.

## Return Value

Return Value The height of the row. The height doesn’t include intercell spacing and must be greater than zero.

## Discussion

Discussion Implement this method if your table supports varying row heights. Although table views may cache the returned values, you should ensure that this method is efficient. When you change a row’s height you must invalidate the existing row height by calling noteHeightOfRows(withIndexesChanged:).  NSTableView automatically invalidates its entire row height cache in response to calls to reloadData() or noteNumberOfRowsChanged(). If you call view(atColumn:row:makeIfNecessary:) or rowView(atRow:makeIfNecessary:) within your implementation of this method, the table view throws an exception. important: To avoid the possibility of a hang due to unexpected recursion, don’t call geometry-calculating methods such as bounds,  rect(ofColumn:), or any NSTableView method that calls tile() within your implementation of this method, such as intercellSpacing. To confirm your code isn’t inadvertently causing any calls to tile(), set a breakpoint on tile() in Xcode.

## See Also

### Setting row and column size

- [tableView(_:sizeToFitWidthOfColumn:)](appkit/nstableviewdelegate/tableview(_:sizetofitwidthofcolumn:).md)