监控键盘事件

<_element_ ng-keyup="_expression_">

import { Component } from '@angular/core';
Component({
  selector: 'app-key-up4',
  template: `
<input #box (keyup.enter)="update(box.value, $event)" (blur)="update(box.value)">`
})
export class KeyUpComponent_v4 {
  value = '';
  update(value: string, event: any) { this.value = value; }
}

常用的过滤有

(keyup.enter)    // 按键并回车
(keyup.space)    // 按键并空格
(keyup.control)  // 按键并ctrl
(keyup.shift)    // 按键并shift
(keyup.alt)      // 按键并alt
(keyup.1)        // 按键1触发
(keyup.，)       // 按键,触发
(keyup.3)        // 按键并alt

不支持一些具有正则含义的符号，
如 / ? * 等

EventManager事件

import { EventManager } from '@angular/platform-browser';
import { Component, OnInit } from '@angular/core';
@Component({
  selector: 'app-demo',
  templateUrl: './demo.component.html',
  styleUrls: ['./demo.component.css']
})
export class DemoComponent implements OnInit {
  constructor(private eventManager: EventManager) { }
  this.eventManager.addGlobalEventListener('window', 'keydown', (event:any) => {
    console.log('监听到键盘按下事件了',event);
    if(event.keyCode == 37 || event.key == 38 || event.key == 39 || event.key == 40){
        //监听到 上下左右 的键盘按下事件时，调用我自己的rePosition()方法~
        this.rePosition(event.keyCode) ;
    }
});
}