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html - 在Angular中将数据从父组件传递到子组件时出现HTML错误

问题描述

在这里，我将数据从父母传递给孩子，并尝试使用这些数据绘制图表。这是我在子组件中的图形绘制方法createGraph(divName, chartDataInfo)。在这里我试图绘制 2 个图表。

  export class ViewComponent implements OnInit{
      lineChart = ['line_chart1', 'line_chart2', 'line_chart3'];
      value = ['33.5M', '67.9M', '90.9M', '09.9M'];
      names = ['Bookings', 'Modifications','cancellations',  'Revenue' ];
      bookingInfo = [];
      mdfInfo = [];
    
      ngOnInit() {
         this.getInfo();
         this.getBookingInfo();
        }
    
      getBookingInfo() {
              const params = [];
              params.push({code: 'dateType', name: 'BOOKING'});
              params.push({code: 'fromDate', name: '2019-01-01'});
              params.push({code: 'toDate', name: '2019-12-31'});
    
              this.ServiceHandler.getTxnInfo([], params).subscribe(
                bookings => {
                  this.bookingInfo = bookings.responseObj.txnValues;
                  console.log(this.bookingInfo);
              });
          }
    
       getInfo(){
        const params = [];
        params.push({code: 'fromDate', name: '2019-01-01'});
        params.push({code: 'toDate', name: '2019-12-31'});
        this.ServiceHandler.getMdfInfo([], params).subscribe(
          modifications => {
            this.mdfInfo = modifications.responseObj.txnValues;
            this.modificationTtcSum = modifications.responseObj.ttcSum;
           });
      }
    
    }

这是我的dashboard.component.html

<app-chips [lineChart]="lineChart[0]" [value] = "value[0]" [name] = "names[0]" [mdfInfo] = "mdfInfo"></app-summary-chips>
<app-chips [lineChart]="lineChart[1]" [value] = "value[1]" [name] = "names[1]" [bookingInfo] = "bookingInfo"></app-summary-chips>

这是我的子组件。因此，我在this.createGraph(this.lineChart, this.mdfInfo);里面打了 2 次电话ngOnChanges(changes: SimpleChanges)。但是当我喜欢这两个图表时，两个图表都没有出现。当我在this.createGraph(this.lineChart, this.mdfInfo)里面只打一次电话ngOnChanges(changes: SimpleChanges)，同时我只使用<app-summary-chips>一次选择器时，一个图表正在绘制。原因是什么？

export class ChipsComponent implements OnInit {
  @Input('lineChart') lineChart: string;
  @Input('value') value: string;
  @Input('name') name: string;
  @Input() bookingInfo = [];
  @Input()  mdfInfo = [];

  ngOnChanges(changes: SimpleChanges) {
    console.log(this.bookingInfo);
    console.log(this.mdfInfo );
    this.createGraph(this.lineChart, this.mdfInfo);
    this.createGraph(this.lineChart, this.bookingInfo);
    }

   createGraph(divName, chartDataInfo) {
    am4core.useTheme(am4themesAnimated);
  
    const chartNameChartTTV = am4core.create(divName, am4charts.XYChart);
    chartNameChartTTV.width = am4core.percent(100);
    chartNameChartTTV.height = am4core.percent(100);
    console.log(this.bookingInfo);
    chartNameChartTTV.padding(0, 0, 0, 0);
    chartNameChartTTV.data = [];

    for (let i = 0; i < chartDataInfo.length; i++) {
      const booking = chartDataInfo[i];
      console.log(booking);
      chartNameChartTTV.data.push({date: booking.time, value: booking.ttc});
    }

    chartNameChartTTV.colors.list = [
      am4core.color('rgba(4, 69, 142, 1)'),
    ];

    // Create axes
    const dateAxis = chartNameChartTTV.xAxes.push(new am4charts.DateAxis());
    const valueAxis = chartNameChartTTV.yAxes.push(new am4charts.ValueAxis());

    valueAxis.renderer.grid.template.disabled = true;
    valueAxis.renderer.labels.template.disabled = true;
    dateAxis.renderer.grid.template.disabled = true;
    dateAxis.renderer.labels.template.disabled = true;

// Create series
    const series = chartNameChartTTV.series.push(new am4charts.LineSeries());
    series.dataFields.valueY = 'value';
    series.dataFields.dateX = 'date';
    series.tooltipText = '{value';
    series.fillOpacity = 1;
    series.strokeWidth = 2;
    series.minBulletDistance = 15;
  
  }

}

这是我的chips.component.html

<div class="l-content-wrapper c-summary-chip oh" >
  <div class="c-summary-chip__value">{{value}}</div>
  <div class="c-summary-chip__txt">{{name}}</div>
  <div id= "{{lineChart}}" class="c-summary-chip__graph ">
  </div>
</div>

标签： htmlangulartypescript

解决方案

尝试将代码包装在 if 检查中

createGraph(divName, chartDataInfo) {

    if (divName && chartDataInfo.length) {}
}

由于 ngOnChanges 是一个异步事件，因此无法保证当您在更改中调用该函数时，所有参数都会出现。

也为了调试给 console.log 像这样。

createGraph(divName, chartDataInfo) {
    console.log(divName, chartDataInfo);

    if (divName && chartDataInfo) {}
}

这样，您可以在调用该函数时确认所有必需的数据都在那里。

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