在Angular中，你不能在同一个元素上使用多个结构指令，这会造成严重的混乱和结构，所以你需要在两个独立的嵌套元素中应用它们(或者你可以使用ng-container)，阅读Angular团队的这句话:

One structural directive per host element Someday you'll want to repeat a block of HTML but only when a particular condition is true. You'll try to put both an *ngFor and an *ngIf on the same host element. Angular won't let you. You may apply only one structural directive to an element. The reason is simplicity. Structural directives can do complex things with the host element and its descendents. When two directives lay claim to the same host element, which one takes precedence? Which should go first, the NgIf or the NgFor? Can the NgIf cancel the effect of the NgFor? If so (and it seems like it should be so), how should Angular generalize the ability to cancel for other structural directives? There are no easy answers to these questions. Prohibiting multiple structural directives makes them moot. There's an easy solution for this use case: put the *ngIf on a container element that wraps the *ngFor element. One or both elements can be an ng-container so you don't have to introduce extra levels of HTML.

所以你可以使用ng-container (Angular4)作为包装器(将从dom中删除)，如果你有class或其他一些属性，可以使用div或span:

<div class="right" *ngIf="show">
  <div *ngFor="let thing of stuff">
    {{log(thing)}}
    <span>{{thing.name}}</span>
  </div>
</div>

你不能在同一个元素上使用ngFor和ngIf。你所能做的就是推迟填充你在ngFor中使用的数组，直到你的例子中的切换被单击。

这里有一个基本的(不是很好的)方法:http://plnkr.co/edit/Pylx5HSWIZ7ahoC7wT6P

<！——因为angular2稳定发布的多个指令不支持单个元素(来自文档)，你仍然可以像下面这样使用它——> < ul类= "列表组" > <template ngFor let-item [ngForOf]="stuff" [ngForTrackBy]="trackBy_stuff"> <李* ngIf = " item.name " class = " list-group-item > {{item.name}} < /李> < /模板> < / ul >

你也可以使用ng-template(而不是template。在同一个HTML元素上同时应用*ngFor和ngIf，请参见使用模板标签的注意事项)。下面是一个例子，你可以同时使用*ngIf和*ngFor来处理angular表中的同一个tr元素。

<tr *ngFor = "let fruit of fruiArray">
    <ng-template [ngIf] = "fruit=='apple'>
        <td> I love apples!</td>
    </ng-template>
</tr>

where fruiArray = ['apple'， 'banana'， 'mango'， 'pineapple']。

注意:

只使用template标记而不使用ng-template标记的警告是，它会在某些地方抛出StaticInjectionError。

正如@Zyzle提到的，以及@Günter在评论(https://github.com/angular/angular/issues/7315)中提到的，这是不支持的。

与

<ul *ngIf="show">
  <li *ngFor="let thing of stuff">
    {{log(thing)}}
    <span>{{thing.name}}</span>
  </li>
</ul>

当列表为空时，没有空的<li>元素。甚至<ul>元素也不存在(正如预期的那样)。

填充列表时，没有多余的容器元素。

@Zyzle在他的评论中提到的github讨论(4792)也提出了另一个解决方案，使用<模板>(下面我使用您的原始标记‐使用<div>s):

<template [ngIf]="show">
  <div *ngFor="let thing of stuff">
    {{log(thing)}}
    <span>{{thing.name}}</span>
  </div>
</template>

这个解决方案也没有引入任何额外/冗余的容器元素。

在Angular中，你不能在同一个元素上使用多个结构指令，这会造成严重的混乱和结构，所以你需要在两个独立的嵌套元素中应用它们(或者你可以使用ng-container)，阅读Angular团队的这句话:

One structural directive per host element Someday you'll want to repeat a block of HTML but only when a particular condition is true. You'll try to put both an *ngFor and an *ngIf on the same host element. Angular won't let you. You may apply only one structural directive to an element. The reason is simplicity. Structural directives can do complex things with the host element and its descendents. When two directives lay claim to the same host element, which one takes precedence? Which should go first, the NgIf or the NgFor? Can the NgIf cancel the effect of the NgFor? If so (and it seems like it should be so), how should Angular generalize the ability to cancel for other structural directives? There are no easy answers to these questions. Prohibiting multiple structural directives makes them moot. There's an easy solution for this use case: put the *ngIf on a container element that wraps the *ngFor element. One or both elements can be an ng-container so you don't have to introduce extra levels of HTML.

所以你可以使用ng-container (Angular4)作为包装器(将从dom中删除)，如果你有class或其他一些属性，可以使用div或span:

<div class="right" *ngIf="show">
  <div *ngFor="let thing of stuff">
    {{log(thing)}}
    <span>{{thing.name}}</span>
  </div>
</div>