我正在尝试在我的 Angular 项目中实现 chart.js.编译时没有任何错误，但图表没有显示.我不知道为什么.

I'm trying implement chart.js in my angular project. There're not any error when compiling but the chart isn't showed. I don't know why.

这是chartjs.component.html

This is chartjs.component.html

<canvas id="canvas">{{chart}}</canvas>

这是 chartjs.component.ts

This is chartjs.component.ts

import { Component, OnInit } from '@angular/core';
import { Chart } from "chart.js";

@Component({
  selector: 'app-chartjs',
  templateUrl: './chartjs.component.html',
  styleUrls: ['./chartjs.component.scss']
})
export class ChartjsComponent implements OnInit {
  public chart: any = null;

  ngOnInit() {
  this.chart = new Chart("canvas", {
    type: 'bar',
    data: {
        labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
        datasets: [{
            label: '# of Votes',
            data: [12, 19, 3, 5, 2, 3],
            backgroundColor: [
                'rgba(255, 99, 132, 0.2)',
                'rgba(54, 162, 235, 0.2)',
                'rgba(255, 206, 86, 0.2)',
                'rgba(75, 192, 192, 0.2)',
                'rgba(153, 102, 255, 0.2)',
                'rgba(255, 159, 64, 0.2)'
            ],
            borderColor: [
                'rgba(255,99,132,1)',
                'rgba(54, 162, 235, 1)',
                'rgba(255, 206, 86, 1)',
                'rgba(75, 192, 192, 1)',
                'rgba(153, 102, 255, 1)',
                'rgba(255, 159, 64, 1)'
            ],
            borderWidth: 1
        }]
    },
    options: {
        scales: {
            yAxes: [{
                ticks: {
                    beginAtZero:true
                }
            }]
        }
    }
});





  }

}

我在dashboard.component.html中名为<app-chartjs></app-chartjs>的选择器中调用它

And i'm calling it in a selector called <app-chartjs></app-chartjs> in dashboard.component.html

我还在angular.json的部分脚本中添加了"node_modules/chart.js/dist/Chart.js".

I also added "node_modules/chart.js/dist/Chart.js" in the section script of angular.json.

任何解决方案请...

推荐答案

你需要将<app-chartjs></app-chartjs>包裹在*ngIf 或者干脆在 <app-chartjs>

<div [hidden]="!chart">
    <canvas class="my-4 w-100" id="canvas" width="900" height="380">{{chart}}</canvas>
</div>