使用segue在Swift中在ViewControllers之间传递数据

Question

我在我正在观看的教程中完美工作的代码存在问题。我看到，在本教程中，他们使用的是斯威夫特1我觉得我有斯威夫特2 第一viewcontroler：

import UIKit 

    class ViewController: UIViewController { 

    @IBOutlet weak var textfield1: UITextField! 


    override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 
    } 

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

    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { 
    var DestViewController : ViewTwo = segue.destinationViewController as ViewTwo // here is where I get the error 

    } 

我应该怎么改？ 感谢

Answer 1

var DestViewController : ViewTwo = segue.destinationViewController as ViewTwo // here is where I get the error 

将需要

var destViewController : ViewTwo = segue.destinationViewController as! ViewTwo // here is where I get the error 

通知!as但是这可能会为Force unwrapping目的地视图崩溃的ViewTwo在未来的时候也未必。

更换

if let destViewController = segue.destinationViewController as? ViewTwo { 
    //Do stuff to the destination controller here 
}