Vue中父组件调用子组件的方法

场景

SpringBoot+Vue+Echarts实现选择时间范围内数据加载显示柱状图：

https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/121555526

在上面的博客页面是父组件，时间选择器是父组件的标签，柱状图是引用的子组件。

实现在父组件选择时间后调用子组件的方法重新渲染柱状图。

注：

博客：
https://blog.csdn.net/badao_liumang_qizhi
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实现

1、子组件BarChartDataRange声明name属性

export default {
  name: "BarChartDateRange",
  data() {
    return {

2、父组件中引入子组件

import BarChartDateRange from "@/components/Echarts/BarChartDateRange";

export default {
  name: "Blog",
  components: {
    BarChartDateRange,
  },
  data() {
    return {

3、父组件中添加子组件显示并设置ref属性

<BarChartDateRange ref="BarChartDateRange"></BarChartDateRange>

4、父组件中调用子组件方法

this.$refs.BarChartDateRange.getSelectedRangeList(val);

5、子组件完整代码

<template>
  <div :style="{ height: '300px',  '300px' }" />
</template>

<script>
import echarts from "echarts";
require("echarts/theme/macarons"); // echarts theme
import request from '@/utils/request'
import { formatDate } from "@/utils/index";

export default {
  name: "BarChartDateRange",
  data() {
    return {
      chart: null,
      typeData: [
        { product: "2021.11.23", 博客数: 20 },
        { product: "2021.11.24", 博客数: 30 },
        { product: "2021.11.25", 博客数: 35 },
        { product: "2021.11.26", 博客数: 43 },
      ],
      yAxisMax: 0,
      queryParam: {
        beginDate: null,
        endDate: null,
      },
    };
  },
  created() {
    //默认开始时间为一周前
    this.queryParam.beginDate = formatDate(
      new Date().getTime() - 60 * 1000 * 60 * 24 * 6
    );
    //默认结束时间时间当前时间
    this.queryParam.endDate = formatDate(new Date().getTime());
    this.getList().then((response) => {
      var res = response.data;
      if (res) {
        //清空柱状图的数据源
        this.typeData = [];
        //遍历后台响应数据，构造柱状图数据源
        for (var key in res) {
          this.typeData.push({ product: key, 博客数: res[key] });
        }
      }
      this.initChart(this.typeData);
    });
  },
  mounted() {},
  methods: {
    //调用后台接口查询数据
    getList() {
      return request({
        url: "/system/blog/list",
        method: "get",
        params: this.queryParam,
      });
    },
    //父组件调用子组件的该方法进行重新渲染柱状图
    getSelectedRangeList(range) {
      var startDate = range[0];
      var endDate = range[1];
      this.queryParam.beginDate = startDate;
      this.queryParam.endDate = endDate;
      this.getList().then((response) => {
        var res = response.data;
        if (res) {
          this.typeData = [];
          for (var key in res) {
            this.typeData.push({ product: key, 博客数: res[key] });
          }
        }
        this.initChart(this.typeData);
      });
    },
    initChart(typeData) {
      this.chart = echarts.init(this.$el, "macarons");
      this.chart.setOption({
        tooltip: {
          trigger: "axis",
          axisPointer: {
            // 坐标轴指示器，坐标轴触发有效
            type: "shadow", // 默认为直线，可选为：'line' | 'shadow'
          },
        },
        grid: {
          top: 10,
          left: "2%",
          right: "2%",
          bottom: "3%",
          containLabel: true,
        },
        legend: {
          //图例
          data: ["博客数"],
        },
        xAxis: [
          {
            type: "category",
            axisPointer: {
              type: "shadow",
            },
            axisLabel: {
              interval: 0,
              rotate: 40,
            },
          },
        ],
        yAxis: [
          {
            type: "value",
            name: "单位：(条)",
            min: 0,
            max: 30,
            interval: 10,
            axisLabel: {
              formatter: "{value}",
            },
          },
        ],
        dataset: {
          source: typeData,
        },
        series: [
          {
            name: "博客数",
            type: "bar",
            barWidth: "40%",
          },
        ],
      });
    },
  },
};
</script>

6、父组件完整代码

<template>
  <div>
    <div>
      <BarChartDateRange ref="BarChartDateRange"></BarChartDateRange>
    </div>
    <div class="block">
      <el-date-picker
        size="large"
        type="daterange"
        v-model="value1"
        range-separator="至"
        start-placeholder="开始日期"
        end-placeholder="结束日期"
        @change="dateSelectChange"
        :value-format="dateFormat"
      >
      </el-date-picker>
    </div>
  </div>
</template>
<script>
import BarChartDateRange from "@/components/Echarts/BarChartDateRange";

export default {
  name: "Blog",
  components: {
    BarChartDateRange,
  },
  data() {
    return {
      value1: "",
      dateFormat: "yyyy-MM-dd",
    };
  },
  created() {
  },
  methods: {
    /** 查询博客列表 */
      dateSelectChange(val) {
      if (val) {
        var startDate = new Date(val[0]).getTime();
        var endDate = new Date(val[1]).getTime();
        debugger;
        if (endDate - startDate > 6 * 24 * 60 * 60 * 1000) {
          this.$message({
            message: "所选时间范围不能大于7天",
            type: "warning",
          });
        }else{
           this.$refs.BarChartDateRange.getSelectedRangeList(val);
        }
      }
    },
  },
};
</script>