Ionic 2:找不到“object"类型的不同支持对象“[object Object]".NgFor 仅支持绑定到 Iterables，例如 Arrays [英] Ionic 2: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays

问题描述

我正在尝试使用以下方法从我的服务类中的 firebase 检索数据:

I am trying to retrieve data from firebase in my service class using:

return this.http.get('https://myfirstfirebaseproject-6da6c.firebaseio.com/products.json')
    .map(res => res.json());

在 home.ts 中，然后我使用以下方式订阅它:

In home.ts, I then subscribe to it using:

        this.productService.fetchProducts()
            .subscribe(data => {
              console.log(data)
              this.products = data;
            });

我输出到 home.html 使用:

I output to home.html using:

<ion-card ion-item *ngFor="let product of products; let i = index" (click)="onItemClick(product)">
    <ion-card-header>
      {{ product.date | date }}
    </ion-card-header>
    <ion-card-content>
      <ion-card-title>
        {{ product.title }}
      </ion-card-title>
      <p>
        {{ product.content }}
      </p>
    </ion-card-content>
  </ion-card>    

但我不断收到错误

错误:找不到类型为object"的不同支持对象[object Object]".NgFor 只支持绑定到 Arrays 等 Iterables.

Error: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays.

我尝试查看类似的问题，但无济于事.请帮忙.

I tried looking at similar issues but to no avail. Please help.

推荐答案

请检查您的 JSON.https://myfirstfirebaseproject-6da6c.firebaseio.com/products.json它返回一个对象而不是数组.这就是为什么你不能在 ngFor 中使用返回的数据.

Please check your JSON. https://myfirstfirebaseproject-6da6c.firebaseio.com/products.json It returns an Object not an Array. That is why you cannot use returned data in ngFor.

{
    -KiTWPuI_TYt0b_Qi03Y: {
    amount: 0,
    category: "Baby",
    content: "I love cricket",
    date: "2017-03-01",
    title: "Cricket"
    },
    -Kid7fghtlxkyrOChQPk: {
    amount: "111",
    category: "Book",
    content: "updated content",
    date: "2017-04-01",
    title: "Cycling"
    },
    d9e7545c-90a3-4a57-97ab-ea3bf9171023: {
    amount: "12",
    category: "Baby",
    content: "COnten1",
    date: "2017-01-01",
    title: "Title2"
    }
}

试试这个:

<ion-card ion-item *ngFor="let key of keys; let i = index" (click)="onItemClick(key)">
    <ion-card-header>
      {{ products[key].date | date }}
    </ion-card-header>
    <ion-card-content>
      <ion-card-title>
        {{ products[key].title }}
      </ion-card-title>
      <p>
        {{ products[key].content }}
      </p>
    </ion-card-content>
  </ion-card>

在您的 component.ts 中:

In your component.ts:

keys: string[];
...
this.productService.fetchProducts()
            .subscribe(data => {
              console.log(data)
              this.products = data;
              this.keys = Object.keys(this.products);
            });

并相应地修改您的 onItemClick().

And modify your onItemClick() accordingly.

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