Swift2 swift 2中的委托错误

我在运行应用程序后传递数据时遇到问题。我正在尝试在选择表视图单元格后更改上一个视图控制器的标签 有人能帮我去那里吗

视图控制器

和tableview控制器 导入UIKit 协议SendbackDelegate:类{ func sendNameToPreviousVC（城市：字符串） }

错误为line

VCOne.delegate=self

---

error=

类型“AircraftSearch”的值没有成员“delegate”

该行可能是

self.delegate = VCOne

---

由于

self

是

SelectedCity

，具有

delegate

属性，

VCOne

类型为

AircraftSearch

，因此是

SendbackDelegate

SelectCity，而在于

labelcity

似乎是

nil

-为什么会有

无论如何？在您在问题中发布的代码中，它被定义为
UILabel，因此您不需要在稍后的过程中将其展开。
class SelectedCity: UITableViewController {
    var toTake = [String]()
    var selecteCity = String()
    weak var delegate: SendbackDelegate? = nil

    override func viewDidLoad() {
        super.viewDidLoad()


    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source


    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return toTake.count ?? 0

    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("stcell", forIndexPath: indexPath) as? mAndMCell

        let nameCity = toTake[indexPath.row]
        print(nameCity)

        cell!.nameCityLabel.text = nameCity
        return cell!
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath){

        let indexPath = tableView.indexPathForSelectedRow!
        let currentCell = tableView.cellForRowAtIndexPath(indexPath) as! mAndMCell!

        selecteCity = currentCell.nameCityLabel!.text as String!

        sendBackIdCity(selecteCity)
        navigationController?.popViewControllerAnimated(true)



    }
    func sendBackIdCity(name: String){
        self.delegate?.sendNameToPreviousVC(name)

    }

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        if segue.identifier == "backCitySegue"{
            var VCOne = segue.destinationViewController as? AircraftSearch
                VCOne.delegate = self


        }
    }



}

self.delegate = VCOne