不能从 myCoustomClass downCast

Question

class MyCViewContollerClass:UIViewController{

    var button = UIButton()
}

let storyBoard = UIStoryboard()
let viewController = storyBoard.instantiateViewController(withIdentifier: "vc") as! MyCViewContollerClass

Answer 1

您需要从文件加载故事板：

let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)

或者，如果您没有故事板，您可以通过编程方式创建视图控制器：

let viewController = MyCViewControllerClass()

不能从 myCoustomClass downCast

Cant downCast from myCoustomClass

swift

downcast