问：从sb.instantiateViewController创建一个vc（withIdentifier :)不能在swift中使用它的属性

Question

从vc10创建sb.instantiateViewController(withIdentifier:)，无法使用其property甚至将其类型转换为ViewController10。

以下是我的代码：

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

您应该在初始化时将其转换为ViewController10：

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