Angular：带* ngClass的条件类

Question

我的Angular代码有什么问题？我正进入（状态：

Cannot read property 'remove' of undefined at BrowserDomAdapter.removeClass ...

的HTML

<ol class="breadcrumb">
    <li *ngClass="{active: step==='step1'}" (click)="step='step1; '">Step1</li>
    <li *ngClass="{active: step==='step2'}"  (click)="step='step2'">Step2</li>
    <li *ngClass="{active: step==='step3'}" (click)="step='step3'">Step3</li>
</ol>

Answer 1

Angular版本2，…，9提供了几种有条件地添加类的方法：

第一类

[class.my-class]="step=='step1'"

第二类

[ngClass]="{'my-class': step=='step1'}"

和多个选项：

[ngClass]="{'my-class': step=='step1', 'my-class2':step=='step2' }"

第三类

[ngClass]="{1:'my-class1',2:'my-class2',3:'my-class4'}[step]"

四类

[ngClass]="(step=='step1')?'my-class1':'my-class2'"