问题描述
我有一个标签，该标签具有与实例内部变量的绑定。
更改变量后，我可以打印出新内容，但标签保留原始内容。
I have a label with a binding to a variable inside an instance.When I change the variable, I can print out the new content but the label keeps the original content.
class myClass: NSObject {
var text : String = "Initial"
override init() {
text = "Init"
}
func change() {
text = "Changed"
}
}
@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
var instance = myClass()
func applicationDidFinishLaunching(aNotification: NSNotification) {
// Insert code here to initialize your application
instance.change()
print(instance.text)
}
func applicationWillTerminate(aNotification: NSNotification) {
// Insert code here to tear down your application
}
}
print（instance.text）给我已更改，但标签保留初始化。
print(instance.text) gives me "Changed" but the label keeps "Init".
在这种情况下为什么绑定不起作用？
Why does the binding not work in this case?
标签具有绑定到App Controller self.instance.text绑定
The label has a "Bind to App Controller" "self.instance.text" binding
谢谢
推荐答案
您可以使用dynamic修饰符来要求动态地访问成员通过Objective-C运行时调度。几乎不需要动态调度。但是，在使用诸如键值观察之类的API时很有必要。
You can use the dynamic modifier to require that access to members be dynamically dispatched through the Objective-C runtime. Requiring dynamic dispatch is rarely necessary. However, it is necessary when using using APIs like key–value observing.
绑定使用键值观察。将 text 属性更改为 dynamic var text：String 和 var实例转换为动态var实例。
Bindings use key–value observing. Change the text property to dynamic var text : String and var instance to dynamic var instance.
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