javascript - 无法在 Angular 2 中从父组件更新子组件 View

Question

朋克:Here

我有一个用于渲染的子组件 chartist.component chartist charts

在我的父组件 app.ts 中，我调用 chartist.component 两次来渲染折线图和条形图

在父组件中，我有按钮来刷新折线图和条形图，它们只是更改数据变量中的数据，然后传递给子组件以呈现图表。

我的问题是，图表仅在单击刷新按钮时更新一次。我想在每次数据对象发生变化时更新图表。

app.ts(父组件):

import {Component, NgModule, OnInit, AfterViewInit} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import {ChartistChart} from './chartist.component'

@Component({
  selector: 'my-app',
  templateUrl: './src/app.html',,
})
export class App implements OnInit, AfterViewInit {
  name:string;
  data: any;
  isFirst:true;
  dataIndex:number;
  allData:any;

  constructor() {
    this.name = 'Angular2'
    this.dataIndex=0;
    this.allData=[{chart data1},{chart data 2}];
  }

   ngOnInit() {  
    this.getAllCharts();
  }

   ngAfterViewInit() {}

  public getAllCharts(){
    this.data= this.allData[this.dataIndex];
    return this.allData[this.dataIndex];
  }

  public updateLineChart(){
    this.isFirst  = !this.isFirst;
    this.dataIndex = this.isFirst?0:1;
    this.data.simpleLineData = this.allData[this.dataIndex].simpleLineData;
    this.data.simpleLineOptions = this.allData[this.dataIndex].simpleLineOptions;
  }

  public updateBarChart(){
    this.isFirst  = !this.isFirst;
    this.dataIndex = this.isFirst?0:1;
    this.data.simpleBarData = this.allData[this.dataIndex].simpleBarData;
    this.data.simpleBarOptions = this.allData[this.dataIndex].simpleBarOptions;
  }
}

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App, ChartistChart ],
  bootstrap: [ App ]
})
export class AppModule {}

app.html:

<div style="width:100%; height:350px">
    <button (click)="updateLineChart()">Update Line chart</button> DataIndex: {{dataIndex}}
    <chartist-chart *ngIf="data" chartistChartClass="ct-chart" chartistChartType="Line" [chartistChartData]="data['simpleLineData']"
              [chartistChartOptions]="data['simpleLineOptions']">
            </chartist-chart>
    </div>
          <br/>  <br/>    
    <div style="width:100%; height:350px">
    <button (click)="updateBarChart()">Update Bar chart</button> DataIndex: {{dataIndex}}
       <chartist-chart *ngIf="data" chartistChartClass="ct-chart" chartistChartType="Bar" [chartistChartData]="data['simpleBarData']"
              [chartistChartOptions]="data['simpleBarOptions']">
            </chartist-chart>
    </div>

chartist.component.ts(子):

import {
  Component, ViewChild, Input, Output, ElementRef, EventEmitter, ChangeDetectorRef 
} from '@angular/core';



@Component({
  selector: 'chartist-chart',
  templateUrl: './src/chartistChart.html',
  providers: [],
})
export class ChartistChart {

  @Input() chartistChartType: string;
  @Input() chartistChartData: Object;
  @Input() chartistChartOptions: Object;
  @Input() chartistChartResponsive: Object;
  @Input() chartistChartClass: string;
  @Output() onChartReady = new EventEmitter<any>();

  @ViewChild('chartistChart') public _selector: ElementRef;

  private chart;
   constructor(private cdr: ChangeDetectorRef){}

  ngAfterViewInit() {
   console.log('chart init', this.chartistChartData)
    let _self = this;
    _self.chart = new Chartist[_self.chartistChartType](_self._selector.nativeElement,
      _self.chartistChartData,
      _self.chartistChartOptions);

    _self.onChartReady.emit(_self.chart);
    this.cdr.detectChanges();
  }



  ngOnChanges(changes) {
    if (this.chart) {
      console.log('chartistChartData changed: ',this.chartistChartData);
      (<any>this.chart).update(this.chartistChartData, this.chartistChartOptions);
    }
  }

  ngOnDestroy(): void {
    if (this.chart) {
      this.chart.detach();
    }
  }
}

chartistChart.html:

<div #chartistChart class="{{chartistChartClass || ''}}"></div>

Answer 1

您需要做的就是在每次点击按钮时手动调用 this.getAllCharts() ，以便将 this.data 重新分配给新的数据系列:

public updateLineChart() {
  this.dataIndex = this.dataIndex ? 0 : 1;
  this.getAllCharts();
}

public updateBarChart() {
  this.dataIndex = this.dataIndex ? 0 : 1;
  this.getAllCharts();
}

你也可以去掉多余的isFirst标志，dataIndex就足够了。而且您也不需要手动设置 this.data.simpleBarData 和 this.data.simpleLineData，因为它已经作为模板中的 props 传递。

演示: https://plnkr.co/edit/1eyTe5WYFAjL9ssRgdiS?p=preview