ios - Q : create a vc from sb. instantiateViewController(withIdentifier:) 不能在swift中使用它的属性

Question

从sb.instantiateViewController(withIdentifier:)创建一个vc10，不能使用它的属性甚至将它的类型转换为ViewController10 。

下面是我的代码:

vc9:

let sb = UIStoryboard.init(name: "Main", bundle: nil)
var vc10 = sb.instantiateViewController(withIdentifier: "ViewController10")

//vc10.delegate = self // there is the error: Value of type 'UIViewController' hs no member 'delegate'
(ViewController10(vc10)).delegate = self // this did not work too 

self.navigationController!.pushViewController(vc10, animated: true) 

vc10:

var delegate:ViewController9?  // this is the property delegate

Answer 1

当你初始化它时，你应该将它转换为 ViewController10:

var vc10 = sb.instantiateViewController(withIdentifier: "ViewController10") as! ViewController10