angular – 如何观察ng-content中的输入元素变化

以下是HTML结构.

# app.comopnent.html
<form>
  <textbox>
    <input type="text">
  </textbox>
</form>

# textbox.component.html
<div class="textbox-wrapper">
  <ng-content>
</div>

限制如下.

> TextboxComponent具有ng-content,需要将input元素投影到它.
>输入输入元素时,在TextboxComponent中发出一个事件.
>不要让输入元素具有更多属性,例如< input type =“text”(input)=“event()”>.

我在编写代码,但找不到解决方案……

# input.directive.ts
@Directive({ selector: 'input',... })
export class InputDirective {
  ngOnChanges(): void {
    // ngOnChanges() can observe only properties defined from @Input Decorator...
  }
}

# textbox.component.ts
@Component({ selector: 'textbox',... })
export class TextboxComponent {
  @ContentChildren(InputDirective) inputs: QueryList<InputDirective>;
  ngAfterContentInit(): void {
    this.inputs.changes.subscribe((): void => {
      // QueryList has a changes property,it can observe changes when the component add/remove.
      // But cannot observe input changes...
    });
  }
}