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数据源更改时 Angular 2 子组件不更新

转载 作者:搜寻专家 更新时间:2023-10-30 21:17:52 24 4
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我已经创建了一个表组件,它根据我传入的配置生成一个表。我知道可能有更好的方法来编写可重用的组件,但现在这就是我所拥有的。

基本上,该组件采用带有列和数据源对象的配置,然后将列映射到数据源中的属性。

我的问题是,在某些时候我对表的一个数据源进行了更改,例如我首先清空数组...

this.members.datasource = []

然后我像这样将新数据推送到数据源...

for (let member in members) {
this.members.datasource.push(members[member]);
}

我的问题是,当我执行此操作时,表不会使用数据源中的新数据进行更新。

我在我的组件中使用了 ngDoCheck 函数,它确实在我更改数据源时触发,但没有其他任何反应。

这是所有相关代码和标记...

ip-datatable组件

import { Component, Input, Output, OnInit, EventEmitter, ElementRef, DoCheck } from "@angular/core";

import { ITable } from "./interfaces/index";

@Component({
selector: "ip-datatable",
templateUrl: "./ip-dataTable.component.html"
})
export class IpDataTableComponent implements OnInit, DoCheck {
@Input()
public config: ITable;
public tableData: any;

@Output()
private onRowClick = new EventEmitter();

constructor(private elem: ElementRef) {

}

public ngOnInit() {
// TODO: Decide whether or not to make this more dynamic (ie: excepts functions returning things other than a promise)
if (typeof (this.config.datasource) == "function") {
this.config.datasource()
.then((data: any) => {
this.tableData = data;
});
} else {
this.tableData = this.config.datasource;
}
}

public rowClicked(e:Event) {
this.onRowClick.emit(e);
}

public ngDoCheck() {

}
}

ip-datatable 组件的模板 html

<table class="table table-bordered table-hover">
<thead>
<tr>
<td *ngFor="let column of config.columns">{{column.header}}</td>
</tr>
</thead>
<tbody>
<tr
*ngFor="let item of tableData"
[class]="(config.rowConfig !== undefined) ? config.rowConfig.classes : ''"
(click)="rowClicked($event)" [id]="(item.id !== undefined) ? item.id : ''">
<td *ngFor="let column of config.columns">{{item[column.mapKey]}}</td>
</tr>
</tbody>
</table>

利用 ip-datatable 的组件

import { Component, OnInit, AfterViewInit, ApplicationRef } from "@angular/core";
import { ActivatedRoute } from "@angular/router";
import { EngagementService } from "../../services/engagement.service";

import { EngagementEditModel } from "../../models/index";
import { ITable } from "../../core/components/ip-datatable/interfaces/index";

@Component({
templateUrl: "engagement-context.component.html"
})

export class EngagementContextComponent {
public id: string;
public engagementDetails: EngagementEditModel;

// Temporarily hardcode groups as there is only two available.
public groups: ITable = {
columns: [
{
header: "Name",
mapKey: "name"
}
],
rowConfig: {
classes: "clickable override"
},
datasource: [
{
name: "Owners"
},
{
name: "Users"
}]
};

public members: ITable = {
columns: [
{
header: "Name",
mapKey: "name"
}
],
datasource: []
}

constructor(private engagementService: EngagementService, private route: ActivatedRoute, private appRef: ApplicationRef) {
this.id = route.snapshot.params["id"];
this.engagementService.getEngagementEditDetailsById(parseInt(this.id))
.then((data: EngagementEditModel) => {
this.engagementDetails = data;
console.log(this.engagementDetails); // tslint:disable-line
});
}

public groupClicked(e: Event) {
// Get the element of the event
let elem: IEventElement = e.currentTarget;
// Get the name of the selected node
let groupName = elem.textContent.trim().toLowerCase();
let members = (<any>this.engagementDetails)[groupName];

interface IEventElement extends EventTarget {
textContent?: string;
}

this.members.datasource = [];

for (let member in members) {
this.members.datasource.push(members[member]);
}
}
}

ip-datatable 的 HTML 用法

<div class="row">
<div class="col-md-12">
<section class="section">
<div class="section-body">
<h4 class="section-title">Groups</h4>
<ip-datatable
[config]="groups"
(onRowClick)="groupClicked($event)">
</ip-datatable>
</div>
</section>
</div>
<div class="col-md-12">
<section class="section">
<div class="section-body">
<h4 class="section-title">Members</h4>
<ip-datatable
[config]="members"
></ip-datatable>
</div>
</section>
</div>
</div>

最佳答案

好吧,我的问题是在 ngOnInit 中我将 this.config.datasource 分配给一个名为 tableData 的变量。好吧,当更改发生时,它永远不会被重新分配给该变量,因此通过调用 ngDoCheck 函数,然后将 this.config.datasource 分配给 tableData,我得到了我想要的更改。

鉴于我听说过 ngDoCheck 的性能障碍,如果我开始注意到性能缺陷,我可能会采取其他措施。如果有人可以在评论中对此提供一些见解,我将不胜感激。

关于数据源更改时 Angular 2 子组件不更新,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41274407/

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