* ngfor json数组对象中显示错误 [英] error display in *ngfor json array object
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问题描述
当从rest api获取json数组对象并尝试在ngfor中显示时，失败的原因是
when fetching json array object from rest api and trying to display in ngfor failed with the reason
例外:找不到类型为对象"的其他支持对象"[对象对象]". NgFor仅支持绑定到Iterables，例如数组.在[HomeComponent @ 5:37的索引中]
EXCEPTION: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays. in [indexes in HomeComponent@5:37]
代码
import {Component} from 'angular2/core';
import {HomeService} from './home.services';
import {Index} from './index';
@Component({
selector: 'home-app',
providers: [HomeService],
template: `
<section class="left_side">
<article>
<div class="div_home">
<div class="div_homeIndxPartition">
<div class="div_IndxPartition" *ngFor="#indObj of indexes">
<table width="500px" class="idx_cons_table_det">
<tr>
<th align="center" color="#A9F5F2"><h3>{{indObj.name}} ({{indObj.tracker}})</h3></th>
<th align="center">Value</th>
<th align="center">Change</th>
<th align="center">%</th>
</tr>
<tr>
<td align="center" colspan="1"></td>
<td align="center">{{indObj.value}}</td>
<td align="center">{{indObj.change}}</td>
<td align="center">{{indObj.percent}}%</td>
</tr>
</table>
<br/>
<table width="500px" class="idx_cons_table">
<tr>
<th align="center">High</th>
<th align="center">Low</th>
<th align="center">Open</th>
<th align="center">Close</th>
<th align="center">52 Week High</th>
<th align="center">52 Week Low</th>
</tr>
<tr>
<td align="center">{{indObj.high}}</td>
<td align="center">{{indObj.low}}</td>
<td align="center">{{indObj.open}}%</td>
<td align="center">{{indObj.close}}</td>
<td align="center">{{indObj.yearHigh}}</td>
<td align="center">{{indObj.yearLow}}%</td>
</tr>
</table>
</div>
</div>
</div>
</article>
</section>
`
})
export class HomeComponent {
public indexes:Array<Index>=[];
public error;
constructor(private _service: HomeService){
this.indexes = _service.getIndexes().subscribe(
data => this.indexes = JSON.parse(data),
error => alert(" Error is : " + error),
()=> console.log("finished")
);
console.log(this.indexes);
}
}
JSON数据
[
{
"id": 1,
"name": "FTSE 100",
"ticker": "UKX",
"value": 69875.23,
"change": 100,
"percent": 2.3,
"high": 69875.23,
"low": 69700.89,
"yearHigh": 699999.23,
"yearLow": 680005.23,
"open": 69600.54,
"close": 699000.97,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 2,
"name": "FTSE 250",
"ticker": "MCX",
"value": 465820.85,
"change": 100,
"percent": 2.3,
"high": 465880.12,
"low": 465810.74,
"yearHigh": 478990.34,
"yearLow": 465320.23,
"open": 69600.54,
"close": 699000.97,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 3,
"name": "FTSE All-Share",
"ticker": "ASX",
"value": 236549.23,
"change": 100,
"percent": 2.3,
"high": 236949.23,
"low": 236149,
"yearHigh": 246949.21,
"yearLow": 235549.29,
"open": 236519.23,
"close": 236649.23,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 4,
"name": "Euro Stoxx 50",
"ticker": "STOXX50E",
"value": 123469.87,
"change": 100,
"percent": 2.3,
"high": 123499.87,
"low": 123439.87,
"yearHigh": 123499.87,
"yearLow": 123169.87,
"open": 123465.87,
"close": 123459.87,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 5,
"name": "S&P 500 ",
"ticker": "S500",
"value": 358976.36,
"change": 100,
"percent": 2.3,
"high": 358986.36,
"low": 358946.36,
"yearHigh": 359976.36,
"yearLow": 357976.36,
"open": 358970.36,
"close": 358996.36,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 6,
"name": "Dow Jones I.A.",
"ticker": "INDU",
"value": 456789.36,
"change": 100,
"percent": 2.3,
"high": 456799.36,
"low": 456779.36,
"yearHigh": 456889.36,
"yearLow": 456689.36,
"open": 456729.36,
"close": 456779.36,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 7,
"name": "GOLD",
"ticker": "",
"value": 500,
"change": 100,
"percent": 2.3,
"high": 700,
"low": 300,
"yearHigh": 1500,
"yearLow": 350,
"open": 450,
"close": 470,
"constituents": null,
"runDate": "21/04/2015"
},
{
"id": 8,
"name": "Brent Crude",
"ticker": "",
"value": 112,
"change": 100,
"percent": 2.3,
"high": 115,
"low": 107,
"yearHigh": 200,
"yearLow": 72,
"open": 110,
"close": 115,
"constituents": null,
"runDate": "21/04/2015"
}
]
推荐答案
我认为您在indexes属性中设置的值不是数组而是对象.
I think that the value you set in the indexes property isn't an array but an object.
我会看到以下几个原因:
I would see several reasons for this:
-
您会收到响应，而不是来自
getIndexes方法的有效负载.在这种情况下，可以在此方法中使用map运算符:
You receive the response instead of the payload from the
getIndexesmethod. In this case, you could use themapoperator in this method:
getIndexes() {
return this.http.get(...).map(res => res.json());
}
接收到的有效载荷并不对应于数组，而是其某些属性.在这种情况下，您需要将此属性设置为indexes属性.
如果要遍历对象的属性，则需要实现这样的自定义过滤器:
If you want to iterate over the properties of an object, you need to implement a custom filter like this:
@Pipe({name: 'keyValues'})
export class KeysPipe implements PipeTransform {
transform(value, args:string[]) : any {
let keys = [];
for (let key in value) {
keys.push({key: key, value: value[key]);
}
return keys;
}
}
并像这样使用它:
<div class="div_IndxPartition" *ngFor="#indObj of indexes | keyValues">
(...)
</div>
看到这个问题:
这篇关于* ngfor json数组对象中显示错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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