使用 *ngFor 访问对象的键和值 - access key and value of object using *ngFor

问题：

I am a bit confused about how to get the key and value of an object in angular2 while using *ngFor for iterating over the object.我对如何在使用*ngFor迭代对象时在 angular2 中获取对象的key和value感到有些困惑。 I know in angular 1.x there is a syntax like我知道在 angular 1.x 中有类似的语法

ng-repeat="(key, value) in demo"

but I don't know how to do the same in angular2.但我不知道如何在 angular2 中做同样的事情。 I have tried something similar, without success:我尝试过类似的东西，但没有成功：

    <ul>
      <li *ngFor='#key of demo'>{{key}}</li>
    </ul>

    demo = {
        'key1': [{'key11':'value11'}, {'key12':'value12'}],
        'key2': [{'key21':'value21'}, {'key22':'value22'}],
      }

Here is a plnkr with my attempt: http://plnkr.co/edit/mIj619FncOpfdwrR0KeG?p=preview这是我尝试的 plnkr： http ://plnkr.co/edit/mIj619FncOpfdwrR0KeG?p=preview

How can I get key1 and key2 dynamically using *ngFor ?如何使用*ngFor动态获取key1和key2 ？ After searching extensively, I found the idea of using pipes but I don't know how to go about it.在广泛搜索后，我发现了使用管道的想法，但我不知道如何去做。 Is there any inbuilt pipe for doing the same in angular2?是否有任何内置管道可以在 angular2 中做同样的事情？

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解决方案：

参考一： https://stackoom.com/question/2P6GV
参考二： access key and value of object using *ngFor