问角自定义指令如何初始化构造函数参数？

EN

@Directive({
  selector: '[appBasicDirective]'
})
export class BetterHighlightDirective implements OnInit {

  @HostBinding('style.backgroundColor') backgroundColor = 'transparent';

  constructor(private el: ElementRef, private renderer: Renderer2) { }

  ngOnInit(): void {
    this.renderer.setStyle(this.el.nativeElement, 'background-color', 'blue');
  }

  ......

constructor(private el: ElementRef, private renderer: Renderer2, 
  private foo: ElementRef, private bar: Renderer2) { }