ngIf中未定义的ViewChild

import { Component, ViewChild, AfterViewInit } from '@angular/core';

@Component({
  selector: 'app-example',
  template: `
    <div *ngIf="condition">
      <child-component #child></child-component>
    </div>
  `
})
export class ExampleComponent implements AfterViewInit {
  @ViewChild('child') childComponent: ChildComponent;
  condition: boolean = true;

  ngAfterViewInit() {
    if (this.condition) {
      // 处理ViewChild
      console.log(this.childComponent);
    } else {
      // 处理未定义的ViewChild
      console.log('ViewChild is undefined');
    }
  }
}

<div *ngIf="condition">
  <child-component #child></child-component>
</div>

<div *ngIf="condition">
  {{ child?.property }}
</div>