希望从异步调用中获取angular2 ngfor按钮循环的值

Question

我有一个来自观察者的异步for循环，它是一个数组的对象。我想知道如何在单击按钮时从该数组中获取值？

数组的对象是这样的：{topic：[＆＃34; first choice＆＃34;，＆＃34; second choice＆＃34;，＆＃34; third choice＆＃34; ]}

<button *ngFor = "let choice of (choices | async)?.Topics">
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Answer 1

<button *ngFor = "let choice of (choices | async)?.Topics" 
    (click)="clickHandler(choice)">