Angular 2 HostListener keypress detect escape key?

问题:

I am using the following method to detect keypresses on a page. My plan is to detect when the Escape key is pressed and run a method if so. For the moment I am just attempting to log which key is pressed. However the Escape key is never detected.

@HostListener('document:keypress', ['$event'])
handleKeyboardEvent(event: KeyboardEvent) {
  console.log(event);
  let x = event.keyCode;
  if (x === 27) {
      console.log('Escape!');
  }
}

回答1:

Try it with a keydown or keyup event to capture the Esc key. In essence, you can replace document:keypress with document:keydown.escape:

@HostListener('document:keydown.escape', ['$event']) onKeydownHandler(event: KeyboardEvent) {
    console.log(event);
}

回答2:

It worked for me using the following code:

const ESCAPE_KEYCODE = 27;

@HostListener('document:keydown', ['$event']) onKeydownHandler(event: KeyboardEvent) {
    if (event.keyCode === ESCAPE_KEYCODE) {
        // ...
    }
}

or in shorter way:

@HostListener('document:keydown.escape', ['$event']) onKeydownHandler(evt: KeyboardEvent) {
    // ...
}

回答3:

Modern approach

@HostListener('document:keydown', ['$event']) onKeydownHandler(event: KeyboardEvent) {
    if (event.key === "Escape") {
        // Do things
    }
}

回答4:

keydown and keyup seem to work: http://embed.plnkr.co/VLajGbWhbaUhCy3xss8l/

回答5:

Angular makes this easy with the @HostListener decorator. This is a function decorator that accepts an event name as an argument. When that event gets fired on the host element it calls the associated function.

@HostListener('document:keydown.escape', ['$event']) onKeydownHandler(event: 
    KeyboardEvent) {
    this.closeBlade();
   }