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  "identifier" : "/documentation/AppKit/NSControlTextEditingDelegate/control(_:isValidObject:)",
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# control(_:isValidObject:)

Invoked when the insertion point leaves a cell belonging to the specified control, but before the value of the cell’s object is displayed.

```
@MainActor optional func control(_ control: NSControl, isValidObject obj: Any?) -> Bool
```

## Parameters

`control`

The control whose object value needs to be validated.

`obj`

The object value to validate.

## Return Value

<doc://com.apple.documentation/documentation/Swift/true> if you want to allow the control to display the specified value; otherwise, <doc://com.apple.documentation/documentation/Swift/false> to reject the value and return the cursor to the control’s cell.

## Discussion

This method gives the delegate the opportunity to validate the contents of the control’s cell (or selected cell). In validating, the delegate should check the value in the `object` parameter and determine if it falls within a permissible range, has required attributes, accords with a given context, and so on. Examples of objects subject to such evaluations are an `NSDate` object that should not represent a future date or a monetary amount (represented by an `NSNumber` object) that exceeds a predetermined limit.

## See Also

[`protocol NSControlTextEditingDelegate`](/documentation/AppKit/NSControlTextEditingDelegate)

A set of optional methods implemented by delegates of [`NSControl`](/documentation/AppKit/NSControl) subclasses to respond to editing actions.


---

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