角度：chart.js图表未显示

我正在使用Angular，已经安装了，chart.js但是图表未显示在页面中。

这是我的代码：

dasboard.component.html

<canvas id="myChart" width="400" height="400"></canvas>

dashboard.component.ts

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

@Component({
    selector: 'dashboard',
    templateUrl: './dashboard.component.html',
    styleUrls: ['./dashboard.component.scss']
})
export class DashboardComponent implements OnInit {

    ngOnInit() {
        var myChart = new Chart('myChart', {
            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
                        }
                    }]
                }
            }
        });
    }
}

当我做

console.log('hello');

在dashboard.component.ts中，它正在控制台中打印，但是图形未显示如何解决此问题？