更新到 Swift 3 后的问题 [重复]

Question

我打开了我的一个项目，Xcode 要求我将源更新为Swift 3。单击保存后，我得到了预期的错误。创建fetchRequest 时发生错误。 （第 8 行有错误信息）

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    let appDelegate = UIApplication.shared().delegate as! AppDelegate

    let managedContext = appDelegate.managedObjectContext!

    let fetchRequest = NSFetchRequest(entityName:"Sessions") //<- Error error message: generic parameter 'ResultType' could not be inferred

        do {
            sessions = try managedContext.fetch(fetchRequest) as! [Sessions]
        } catch let error as NSError {
            print("Could not fetch \(error), \(error.userInfo)")
        }

        print("fetched")

        self.tableView.reloadData()
    }
}

Answer 1

我自己也找到了解决方案。我刚从

let fetchRequest = NSFetchRequest(entityName:"Sessions")

到

let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName:"Sessions")