How to programmatically show a window/view controller in Swift 4 for macOS application - swift

Question

I'm trying to programmatically show a window in my macOS application. The reason I want to do it programmatically is because the user clicks a Login button and the resulting function depends on the success of the login. If it was successful, the window is shown; otherwise, it is not.
Here is a screenshot of my Xcode window:
Here's what I'm trying in the code (Alert is a class I created to make showing NSAlert dialogs easier):
#IBAction func btnLogin_Click(_ sender: Any) {
let email = txtEmail.stringValue
if(email.isEmpty) {
Alert.show(parent: view.window!, message: "Email is required.")
return
}
let password = txtPassword.stringValue
if(password.isEmpty) {
Alert.show(parent: view.window!, message: "Password is required.")
return
}
// this does not work, even though I gave the window and view controllers
// both identifiers in the storyboard
self.storyboard?.instantiateController(withIdentifier: NSStoryboard.SceneIdentifier("wcStores"))
}
Apple's documentation for NSStoryboard.SceneIdentifier is pretty much nonexistent, and other methods I've seen seem to pertain to earlier versions of Swift.
What am I doing wrong?

Answer 1

Alright, so this is not what I originally was trying to do, but this way is much better, and what I was really looking for.
let vcStores = self.storyboard?.instantiateController(withIdentifier: NSStoryboard.SceneIdentifier("vcStores"))
as! NSViewController
self.view.window?.contentViewController = vcStores
This will just replace the window's contents with the contents in the view vcStores as defined in Interface Builder.
This video also helped, albeit for iOS and Swift 3. I was trying to create a new NSWindow at first because I'm so used to doing desktop development in Java Swing or C# Windows Forms. But I love how easy it is to just switch out the window contents like this.