Swift在VC之间传递数据

Question

我是Swift的新手，我想知道为什么我从Obj-C翻译的这段代码在这里不起作用。

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "scoreDetail" {
            let indexPath = self.tableView.indexPathForSelectedRow()
            let object = self.fetchedResultsController.objectAtIndexPath(indexPath) as NSManagedObject

            let itemVC: ScoreVC = segue.destinationViewController as ScoreVC
            itemVC.detailItem = object
        }
    }

这是故事板。我从单元格到Show Replace有一个UINavigatorController segue

我点击UITableViewCell

后立即收到此错误消息

Answer 1

问题与Swift无关。 destinationViewController是导航控制器，而不是您的ScoreVC，因此您翻译的代码也不应该有效（如果它具有相同的设置）。它看起来应该是这样的，

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "scoreDetail" {
            let indexPath = self.tableView.indexPathForSelectedRow()
            let object = self.fetchedResultsController.objectAtIndexPath(indexPath) as NSManagedObject

            let nav : UINavigationController = segue.destinationViewController
            let itemVC: ScoreVC =  nav.topViewController as ScoreVC
            itemVC.detailItem = object
        }
    }