数据源更改时 Angular 2 子组件不更新

Question

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>

Answer 1

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。