如何在Angular2中隐藏和替换组件 [英] How to hide and replace a component in Angular2

问题描述

您好，我有一个父级组件(A)，并且有2个子级组件(B和C).父级A默认情况下显示子组件B.现在，当单击父级A上显示的按钮时，它将用子组件C替换子组件B.在angular2中单击按钮后，如何用组件C替换组件B?/p>

Hello i have a parent component (A) and it has 2 child components (B and C). Parent A by default displays child component B. Now when a button is clicked that is displayed on parent A, it replaces child component B with child component C. How can i replace component B with Component C after the button is clicked in angular2?

推荐答案

为此，您可以使用

To do that you can use the *ngIf directive or the hidden property.

请注意区别:

• * ngIf 删除并重新创建元素:

• *ngIf removes and recreates the element:

如果分配给ngIf的表达式的计算结果为假值，则元素已从DOM中删除，否则该元素的克隆为重新插入DOM.

If the expression assigned to ngIf evaluates to a false value then the element is removed from the DOM, otherwise a clone of the element is reinserted into the DOM.

• hidden 使用 display隐藏元素:无

从angular的文档:

显示/隐藏技术对于小型元素树可能很好.我们隐藏大树时应保持警惕；NgIf可能是更安全的选择.在得出结论之前，务必先进行测量.

The show/hide technique is probably fine for small element trees. We should be wary when hiding large trees; NgIf may be the safer choice. Always measure before leaping to conclusions.

检查以下示例:

@Component({
  selector: 'my-app',
  template: `
    <b>Using *ngIf:</b>
    <div *ngIf="!isOn">Light Off</div>
    <div *ngIf="isOn">Light On</div>
    <br />
    <b>Using [hidden]:</b>
    <div [hidden]="isOn">Light Off</div>
    <div [hidden]="!isOn">Light On</div>
    <br />
    <button (click)="setState()">{{ getButtonText() }}</button>
  `
})
export class AppComponent {

  private isOn: boolean = false;

  getButtonText(): string {
    return `Switch ${ this.isOn ? 'Off' : 'On' }`;
  }
  setState(): void {
    this.isOn = !this.isOn;
  }

}

柱塞: http://plnkr.co/edit/7b1eWgSHiM1QV6vDUAB0

为进一步了解 [hidden] ，我指出了这篇文章:

For further reading about [hidden], I indicate this article: http://angularjs.blogspot.com.br/2016/04/5-rookie-mistakes-to-avoid-with-angular.html

希望有帮助.

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