“串？' 不能转换为'NSString'“（Xcode 7迁移后）

Question

你好我正在开发项目（在objective-c中完成它）但是一个类在Swift中被写了。 迁移到XCODE 7 for ios9编译器后回到我的错误：'String？' 代码不能转换为'NSString'：

if let view = self.emailTextField.rightView {
                    if (self.emailTextField.text as NSString).validateEmail() {
                        self.emailTextField.rightView?.alpha = 1
                    } else {
                        self.emailTextField.rightView?.alpha = 0
                    }
                }

来自Swift2老板:)的任何建议？

Answer 1

老板建议：

self.emailTextField.text as NSString成为self.emailTextField.text! as NSString self.emailTextField.text! as NSString

:)