如何将异步数据传递给对象中的子组件（Angular6）

我正在尝试显示从服务器检索的数据（使用Angular 6，Rxjs和Chartjs），并使用该数据呈现图表。如果我使用本地模拟数据，那么一切都会很好地呈现。但是，如果我使用从服务器获取数据，则呈现图形所需的数据不可用，因此这些图表将呈现为空白图表。

简介：组件进行服务调用，并使用该服务调用的响应准备要传递给子组件的对象。但是，到响应准备就绪时，该对象已被发送而没有必要的信息。

服务代码段：

  getAccountsOfClientId(clientID: string): Observable<Account[]> {
    return this.http.get<Account[]>(`${this.BASE_URL}/accounts?client=${clientID}`)
      .pipe(
        tap(accounts => console.log('fetched client\'s accounts')),
        catchError(this.handleError('getAccountsOfClientId', []))
      );
  }

在client-info.component.ts中（用于进行服务调用并准备并将对象传递给子组件的组件）

@Input() client; // received from another component, data is filled

  constructor(private clientAccountService: ClientAccountService) { }

  ngOnInit() {
    this.getAccountsOfClientId(this.client.id);
  }

  ngAfterViewInit() {
    this.updateChart(); // render for pie chart
    this.updateBarChart(); // render for bar chart
  }

  getAccountsOfClientId(clientID: string): void {
    this.clientAccountService.getAccountsOfClientId(this.client.id)
      .subscribe(accounts => this.clientAccounts = accounts);
  }

  updateBarChart(updatedOption?: any): void {
    /* unrelated operations above ... */

    // Create new base bar chart object
    this.barChart = {};
    this.barChart.type = 'bar';
    this.setBarChartData();
    this.setBarChartOptions('Account', 'Balance');
  }

  setBarChartData(): void {

    // field declarations..

    console.log('clientAccounts has length: ' + this.clientAccounts.length); // prints 0
    this.clientAccounts.map((account, index) => {
        // do stuff
    });

    dataset = {
      label: 'Balance',
      data: data,
      ...
    };

    datasets.push(dataset);

    // since clientAccounts was empty at the time this function ran, the "dataset" object doesn't contain
    // the necessary information for the chart to render
    this.barChart.data = {
      labels: labels,
      datasets: datasets
    };
  }

我在寻找改变使用ngOnChanges（在子组件），但是图表数据不更新子组件的“clientAccounts”阵列充满响应之后。

@Input() chart: Chart;
@Input() canvasID: string;
@Input() accountBalanceStatus: string;

ngOnChanges(changes: SimpleChanges) {
  if (changes['accountBalanceStatus'] || changes['chart']) {
    this.renderChart();
  }
}


renderChart(): void {
  const element = this.el.nativeElement.querySelector(`#${this.canvasID}`);

  if (element) {
    const context = element.getContext('2d');

    if (this.activeChart !== null) {
      this.activeChart.destroy();
    }

    this.activeChart = new Chart(context, {
      type: this.chart.type,
      data: this.chart.data,
      options: this.chart.options
    });
  } else {
    console.log('*** Not rendering bar chart yet ***');
  }
}

您能否指出我应该如何继续对此进行研究？

抱歉，很长的问题，谢谢！

编辑：根据要求，模板如下

父级（客户信息）：

<div class='client-info-container'>
  <div class='info-container'>
    <li>Date of Birth: {{ client.birthday | date: 'dd/MM/yyyy'  }}</li>
    <li>Name: {{ client.name }}</li>
    <li>First Name: {{ client.firstname }}</li>
  </div>

  <div class='more-button'>
    <button (click)='openModal()'>More</button>
  </div>

  <div class='chart-container'>
    <div *ngIf='pieChart && client'>
      <app-balance-pie-chart
      [chart]='pieChart' 
      [canvasID]='accountBalancePieChartCanvasID'
      (updateChart)='handlePieChartOnClick($event)'>
      </app-balance-pie-chart>
    </div>

    <div class='bar-chart-container'>
      <div class='checkbox-container'>
        <div *ngFor='let option of cardTypeCheckboxOptions' class='checkbox-item'>
          <input
          type='checkbox' 
          name='cardTypeCheckboxOptions' 
          value='{{option.value}}' 
          [checked]='option.checked'
          [(ngModel)]='option.checked'
          (change)="updateCardTypeCheckboxSelection(option, $event)"/>

          <p>{{ option.name }} {{ option.checked }}</p>
        </div>
      </div>

      <div *ngIf='barChart && client'>
        <!--  *ngIf='client.accounts.length === 0' -->
        <div class="warning-text">This client does not have any accounts.</div>
        <!--  *ngIf='client.accounts.length > 0' -->
        <div>
            <app-balance-account-bar-chart
            [chart]='barChart'
            [canvasID]='accountBarChartCanvasID'
            [accountBalanceStatus]='accountBalanceStatus'>
            </app-balance-account-bar-chart>
        </div>
      </div>

    </div>
  </div> 
</div>

图表：

<div class='bar-chart-canvas-container' *ngIf='chart'>
  <canvas id='{{canvasID}}' #{{canvasID}}></canvas>
</div>