Angular 6 中 ngIf 中的多个条件

Question

我想隐藏一个 div 并想显示另一个我在下面编写的代码

我的问题是我在 ngIf 中使用了多个条件但无法正常工作。单击 "Show sub content1" 后，我想隐藏主要内容并显示 "Sub Content 1"，反之亦然。为此我该怎么办。请帮忙

Answer 1

您刚刚接近结果，查看您的代码看起来就像您在学习一样，干得好！！您必须检查是否启用了任何一个内容，因此您需要隐藏所有三个按钮并显示您的子内容。以下是根据您的要求正确的代码，

<!-- Display all of the SubContents is disable. -->
<div *ngIf="!showSubContent && !showSubContentTwo && !showSubContentThree">
     <button (click)="showSubContent=!showSubContent">Show Sub content1</button>
     <button (click)="showSubContentTwo=!showSubContentTwo">Show Sub content2</button>
     <button (click)="showSubContentThree=!showSubContentThree">Show Sub content3</button> 
     <h2>  Main content </h2>
</div>

<!-- Display if SubContent-1 is enable. -->
<div *ngIf="showSubContent && !showSubContentTwo && !showSubContentThree">
    Sub Content 1 here
    <button (click)="showSubContent=!showSubContent">Show Main Content</button>
</div>

<!-- Display if SubContent-2 is enable. -->
<div *ngIf="showSubContentTwo && !showSubContent && !showSubContentThree">
    Sub Content 2 here
    <button (click)="showSubContentTwo=!showSubContentTwo">Show Main Content</button>
</div>

<!-- Display if SubContent-3 is enable. -->
<div *ngIf="showSubContentThree && !showSubContentTwo && !showSubContent">
    Sub Content 3 here
    <button (click)="showSubContentThree=!showSubContentThree">Show Main Content</button>
</div>

Answer 2

您可以使用 ngSwitch 来简化您的代码：

<div [ngSwitch]="showSubContent">

  <div *ngSwitchDefault>
      <button (click)="showSubContent=1">Show Sub content1</button>
      <button (click)="showSubContent=2">Show Sub content2</button>
      <button (click)="showSubContent=3">Show Sub content3</button> 
      <h2>  Main content </h2>
  </div>

  <div *ngSwitchCase="1">
      Sub Content 1 here
  </div>

   <div *ngSwitchCase="2">
      Sub Content 2 here
  </div>


  <div *ngSwitchCase="3">
      Sub Content 3 here
  </div>

  <button *ngIf="showSubContent" (click)="showSubContent=0">Show Main Content</button>
</div>

Answer 3

这样的作品不需要用那么多条件。这也不直观，无法理解您的逻辑，而是使用 switch

// Define a variable with name content in component
export class AppComponent  {
content = 'mainContent'
constructor() {
}}

<div>
   <button (click)="content='showSubContent'">Show Sub content1</button>
   <button (click)="content='showSubContentTwo'">Show Sub content2</button>
   <button (click)="content='showSubContentThree'">Show Sub content3</button>
 </div>
<div [ngSwitch]="content">

 <div *ngSwitchDefault>
   My Main content
  </div> 
<div *ngSwitchCase="'showSubContent'">
   Sub Content 1 here
   <button (click)="content='showMainContent'">Show Main Content</button>
</div>

<div *ngSwitchCase="'showSubContentTwo'">
   Sub Content 2 here
   <button (click)="content='showMainContent'">Show Main Content</button>
</div>

<div *ngSwitchCase="'showSubContentThree'">
   Sub Content 3 here
   <button (click)="content='showMainContent'">Show Main Content</button>
</div>
</div>

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