我正在尝试用 vue-chartjs 制作一个 vue。当 chartData 道具更新时，我已遵循所有有关重新渲染图表的相关文档。我的图表只会在我调整浏览器窗口大小后更新。
我的 parenttestchart.vue 文件：
<template>
<div>
<h1>Chart datacollection update test</h1>
<p>This component demonstrates fetching data from the server.</p>
<p v-if="!datacollection"><em>Loading...</em></p>
<b-form-select
v-model="testthingSelect.selected"
text="Select testthing"
variant="primary"
:options="testthingSelect.options"
:on-change="changetestthing"
class="m-md-2">
</b-form-select>
<test-chart v-cloak :chart-data="datacollection" :chart-option="options"></test-chart>
</div>
</template>
<script>
import TestChart from './TestChart'
export default {
components: {
TestChart
},
data() {
return {
yAxisValues: [],
datacollection: {},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: false
},
gridLines: {
display: true
}
}],
xAxes: [{
type: "date",
display:true,
gridLines: {
display: false
}
}]
},
legend: {
display: true
},
responsive: true,
maintainAspectRatio: false
},
testthingSelect: {
selected: "EIA/COAL",
disabled: false,
readonly: false,
visible: true,
color: "",
options: [
{
value: null,
text: 'Select a testthing'
},
{
value: "item1",
text: "item1"
},
{
value: "item1",
text: "item1"
},
{
value: "item1",
text: "item1"
}
]
}
}
},
methods: {
changetestthing: async function () {
try {
let response = await this.$http.get(url for my data);
this.datacollection.datasets = [];
this.datacollection.labels = [];
...required data transformations
this.$set(this.datacollection, "labels", labels);
this.$set(this.datacollection, "datasets", datasets);
// this.datacollection.labels = labels;
// this.datacollection.datasets = datasets;
} catch (error) {
console.log(error)
}
}
},
watch: {
'commoditySelect.selected': function () { this.changeCommodity(); }
},
async created() {
// ES2017 async/await syntax via babel-plugin-transform-async-to-generator
// TypeScript can also transpile async/await down to ES5
try {
let response = await this.$http.get(url for my data);
this.datacollection.datasets = [];
this.datacollection.labels = [];
...required data transformations
this.$set(this.datacollection, "labels", labels);
this.$set(this.datacollection, "datasets", datasets);
// this.datacollection.labels = labels;
// this.datacollection.datasets = datasets;
} catch (error) {
console.log(error)
}
} catch (error) {
console.log(error)
}
}
}
我的 TestChart.vue 文件
<script>
import { Line, mixins } from 'vue-chartjs'
const { reactiveProp } = mixins
//Exporting this so it can be used in other components
export default {
extends: Line,
mixins: [reactiveProp],
props: ['chartData', 'options'],
mounted() {
this.renderChart(this.chartData, this.options)
}
}
</script>
因此，这是在选择和更改父 vue 中的数据集合方面起作用的。除非我调整窗口大小，但图表不会重新呈现。当 parenttestchart.vue 最初加载时，我收到以下错误：'Uncaught TypeError: Cannot read property 'transition' of null'。但这似乎没有任何影响，因为调整窗口大小将呈现图表的初始显示。更新数据 changetestthing 方法确实会正确更新数据集合（chartData），但除非我调整窗口大小，否则它不会重新渲染。
如何强制图表重新渲染？我怎样才能在父级中获得对 TestChart 组件的引用？this.TestChart 未定义。我只是想从参考中获取参考，以防我可以手动调用'renderChart'。谢谢。
*** 更新
我能够通过以下修改来更新图表：
我从 changetestthing 方法中删除了以下几行：
this.datacollection.datasets = null;
this.datacollection.labels = null;
并将 datacollection 赋值语句更改为：
this.datacollection = Object.assign({}, this.datacollection, { labels: labels, datasets: datasets });
我不能肯定地说这是最佳实践。根据 vue.js 文档（https://vuejs.org/v2/guide/reactivity.html#Change-Detection-Caveats）
new properties added to the object will not trigger changes. In such
cases, create a fresh object with properties from both the original
object and the mixin object
所以我相信通过不将 datacollection.labels 和 .datasets 属性设置为 null 然后使用 Object.assign 触发更改。我仍然不确定为什么没有使用 mixins 或手动手表触发它们。任何意见表示赞赏。