How to capture or monitor all kind of keyboard event from NSViewController?

import Cocoa

class MyView: NSView {

override init(frame frameRect: NSRect) {
    super.init(frame: frameRect)
}

required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func becomeFirstResponder() -> Bool {
    return true
}

override var acceptsFirstResponder: Bool {
    return true
}

override func keyUp(with event: NSEvent) {
    print("keyUp: keyCode=\(event.keyCode)")
}

// the 'CMD + q' combination will quit the app
// the 'CMD + t' combination will open a font setting window
// the 'CMD + Space' combination will toggle the spotlight search
// the 'CTRL + Space' combination will toggle the input method switching
// why this can't capture the key board event like 'CMD + Space' or 'CMD + t' or 'CMD + q'?
// or how capture those combinations regardless of the system-wide shortcuts?
override func keyDown(with event: NSEvent) {
    print("keyDown: keyCode=\(event.keyCode)")
    if event.modifierFlags.contains(.command) {
        if event.keyCode == 49 {
            print("keyDown: CMD + Space") // if the 'CMD' and 'Space' keys were pressed both, this line is not print
        } else {
            print("keyDown: CMD + others") // here, like 'CMD' and 'j' keys were pressed both, this line is print
        }
    } else if event.modifierFlags.contains(.control) {
        if event.keyCode == 49 {
            print("keyDown: CTRL + Space") // if the 'CTRL' and 'Space' keys were pressed both, this line is not print
        } else {
            print("keyDown: CTRL + others") // here, like 'CTRL' and 'j' keys were pressed both, this line is print
        }
    } else {
        print("keyDown: CMD or CTRL is not pressed")
    }
}

override func flagsChanged(with event: NSEvent) {
    print(#function, event.keyCode)
}

}

class ViewController: NSViewController { override func viewDidLoad() { super.viewDidLoad() }

override func viewWillAppear() {
    super.viewWillAppear()
    let myview = MyView(frame: view.bounds)
    view.addSubview(myview)
}

}