创建多个动态图表 [英] Create multiple dynamic charts

问题描述

我正在开发Web应用程序-MEAN堆栈.我正在尝试使用ChartJS甜甜圈图，但我需要它是完全动态的-首先，图表的数量是动态的(每个图表代表其他东西)，因此有时会是3个，有时是20个.第二，我希望能够访问每个图表以进行实时数据更改.甚至有可能吗?我试图创建一个数组来保存每个图表数据，并使用* ngFor来创建每个图表一个canvas元素，但是它不起作用.

i'm developing a web application - MEAN stack. i'm trying to use ChartJS doughnut chart but i need it to be completely dynamic - first, the number of charts is dynamic (each chart represent something else) so sometimes it will be 3 and sometime 20. second, i want ti be able to access each of the charts for real-time data changing. does it even possible? i tried to create an array that will hold each of the charts data and use *ngFor to create each chart an canvas element but it didn't work.

我的chartjs.component.ts:

import { Component, OnInit } from '@angular/core';
import { DataService } from '../data.service';
import { Chart } from 'chart.js';
import { pieceLabel } from 'chart.piecelabel.js';
import {ElementRef} from '@angular/core';
@Component({
selector: 'app-chartjs',
templateUrl: './chartjs.component.html',
styleUrls: ['./chartjs.component.css']
})
export class ChartjsComponent implements OnInit {
constructor( private _dataService : DataService, private elementRef: ElementRef) { 

}
jsons: any;
NumberOfSystems: Number;
charts = [];
ngOnInit() {
this._dataService.getData().subscribe(data => {
  this.jsons = data
  this.NumberOfSystems = this.jsons.data[0][1].systems.length
  this.createChartsData()
}); 
}
createChartsData()
{
var array=[];
for(var i =0; i<this.NumberOfSystems;i++)
{
var pie ={
  type: 'doughnut',
  data: {
    labels: ["Disks", "Mgmt", "Hardware", "FC", "Vols&Pols"],
    datasets: [
      {
        backgroundColor:["#008000","#008000","#008000","#008000","#008000"],
        data: [20,20,20,20,20]
      }
    ]
  },
  options: {
    title: {
      display: false
    },
    animations: true,
    tooltips: {
      enabled: true
     },
     legend: {
      display: true
    }
  }
};
array.push(pie);
}
this.createCharts(array);
}
createCharts(pieData){
for(var j = 0; j<this.NumberOfSystems;j++)
{
  let htmlRef = this.elementRef.nativeElement.select(`#canvas`+j);
  console.log(htmlRef);
  var tempChart = new Chart(htmlRef,pieData[j]);
  this.charts.push(tempChart);
}   
}
}

这是 chartjs.component.html:

<div>
<canvas *ngFor="let chart of charts; let i = index" id="canvas{{i}}">{{charts}}</canvas>
</div>

在此状态下，ElementRef为空.

in this state, the ElementRef is null.

推荐答案

在您的

画布...添加#yourId

canvas ... add a #yourId

(示例:canvas * ngFor =让图表变成图表；让我= index" id ="canvas {{i}} #yourId")

(example : canvas *ngFor="let chart of charts; let i = index" id="canvas{{i}} #yourId")

然后，您可以使用@ViewChildren('yourId')myCharts:any; (您不能在ngOnInit中使用myCharts，只能在ngAfterViewInit及其之后使用)，这将为您提供一系列图表.

Then you can use @ViewChildren('yourId') myCharts: any; (you can't use myCharts in ngOnInit, only in ngAfterViewInit and after) which will give you your array of charts.

我将不提供更多详细信息，但是您可以使用myCharts中的内容(使用console.log(myCharts)可以查看其中的详细信息)，也可以使用它来更改数据，依此类推.

I won't provide much more detail but you can use what's inside your myCharts (use a console.log(myCharts) to see in detail what's in there), you can use this to change data and so on.

希望这会有所帮助.

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