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# setValue(_:forUndefinedKey:)

Invoked by [`setValue(_:forKey:)`](/documentation/ObjectiveC/NSObject-swift.class/setValue(_:forKey:)) when it finds no property for a given key.

```
func setValue(_ value: Any?, forUndefinedKey key: String)
```

## Parameters

`value`

The value for the key identified by `key`.

`key`

A string that is not equal to the name of any of the receiver’s properties.

## Discussion

Subclasses can override this method to handle the request in some other way. The default implementation raises an `NSUndefinedKeyException`.

## See Also

[`func value(forUndefinedKey: String) -> Any?`](/documentation/ObjectiveC/NSObject-swift.class/value(forUndefinedKey:))

Invoked by [`value(forKey:)`](/documentation/ObjectiveC/NSObject-swift.class/value(forKey:)) when it finds no property corresponding to a given key.


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