Element Checkbox 多选框赋值

<template>
    <el-form :inline="true" label-position="top" label-width="80px" ref="requestUrl" :rules="rules" :model="formdata">
        <el-form-item  label="常见病史：" prop="medicalHistory">
        <el-checkbox-group v-model="medicalHistory">
          <el-checkbox v-for="city in cities" :label="city" :key="city">{{city}}</el-checkbox>
        </el-checkbox-group>
      </el-form-item>
    </el-form>
</template>

<script>
  const cityOptions = ['心脏病', '脑血栓', '糖尿病', '高血压', '高血脂', '肺气肿', '脑中风', '骨质增生', '其他'];
  export default {
    props: ['requestUrl'],
    data() {
      return {
        medicalHistory:[],
        formdata: {},
        cities: cityOptions
      }
    },
    mounted() {
       this.medicalHistory = this.medicalHistorys
       this.formdata = this.requestUrl
    },
    watch:{
      requestUrl(newValue,oldValue){
        this.formdata = newValue
      }
    },
    computed:{
      medicalHistorys:function(){
       return (this.requestUrl.medicalHistory || " " ).split(",")
      }
    },
    methods: {
    }
  }
</script>