对于elseif语句(较少比较)，使用如下语句:(例如，比较三个语句)

<div [ngClass]="step === 'step1' ? 'class1' : (step === 'step2' ? 'class2' : 'class3')"> {{step}} </div>

[ngClass] =…而不是*ngClass。

*仅用于结构型指令的简写语法，例如可以使用

<div *ngFor="let item of items">{{item}}</div>

而不是较长的同等版本

<template ngFor let-item [ngForOf]="items">
  <div>{{item}}</div>
</template>

参见https://angular.io/docs/ts/latest/api/common/index/NgClass-directive.html

<some-element [ngClass]="'first second'"> <某个元素[ngClass] = "(“第一次”,“二”)" >…< /某个元素> <某个元素[ngClass] = "{“第一”:真的,“二”:真的,“第三”:假}" >…< /某个元素> <某个元素[ngClass] = " stringExp | arrayExp | objExp " >…< /某个元素> <some-element [ngClass]="{'class1 class2 class3': true}">

参见https://angular.io/docs/ts/latest/guide/template-syntax.html

<！——用属性>开启/关闭“特殊”类 < div[类。</div> . special]="isSpecial">类绑定是特殊的 <！——绑定到class。Special '胜过类属性——> < div class = "特殊的“ [class.special] = " !isSpecial">这个没有那么特别</div>

<！——用绑定重置/覆盖所有类名——> .使用实例 <div class="bad curly special" (类)= " badCurly " >坏花< / div >

该指令有三种不同的操作方式，这取决于表达式的计算结果是三种类型中的哪一种:

If the expression evaluates to a string, the string should be one or more space-delimited class names. If the expression evaluates to an object, then for each key-value pair of the object with a truthy value the corresponding key is used as a class name. If the expression evaluates to an array, each element of the array should either be a string as in type 1 or an object as in type 2. This means that you can mix strings and objects together in an array to give you more control over what CSS classes appear. See the code below for an example of this.

    [class.class_one] = "step === 'step1'"

    [ngClass]="{'class_one': step === 'step1'}"

对于多个选项:

    [ngClass]="{'class_one': step === 'step1', 'class_two' : step === 'step2' }" 

    [ngClass]="{1 : 'class_one', 2 : 'class_two', 3 : 'class_three'}[step]"

    [ngClass]="step == 'step1' ? 'class_one' : 'class_two'"

你可以使用[ngClass]或[class]。Classname]，两者的工作方式相同。 [class.my-class] = " = = =步step1” 或

[ngClass] = "{“我班”:一步= =“步骤1”}”

两者的效果是一样的!

扩展MostafaMashayekhi对选项二的答案> 你也可以用一个'，'连接多个选项

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

此外，*ngIf也可以在某些情况下使用，通常与*ngFor结合使用

class="mats p" *ngIf="mat=='painted'"

像这样试试。

用“

<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>