# init(identifier:source:destination:performHandler:) Creates a segue that calls a block to perform the segue transition. ``` convenience init(identifier: String?, source: UIViewController, destination: UIViewController, performHandler: @escaping () -> Void) ``` ## Parameters `identifier` The identifier you want to associate with this particular instance of the segue. You can use this identifier to differentiate one type of segue from another at runtime. `source` The view controller visible at the start of the segue. `destination` The view controller to display after the completion of the segue. `performHandler` A block to be called when the segue’s [`perform()`](/documentation/UIKit/UIStoryboardSegue/perform()) method is called. ## Return Value An initialized segue object. ## Discussion You use this method as an alternative to creating a subclass. Your perform handler should do all of the work necessary to transition between the source and destination view controllers, exactly as if you were implementing the [`perform()`](/documentation/UIKit/UIStoryboardSegue/perform()) method. ## See Also [`perform()`](/documentation/UIKit/UIStoryboardSegue/perform()) Performs the visual transition for the segue. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)