// 给下拉框绑定下拉列表的索引
<el-select v-model="value" placeholder="请选择" style="float:left" @change="selectNum(value)">
     <el-option
         v-for="item in options"
         :key="item.value"
         :label="item.label"
         :value="item.value">
     </el-option>
</el-select>

// 加载组件：每次下拉框监听则给changValue新赋值，如果下拉options的value从0开始则绑定组件时不用-1
<component :is="componentName[changValue - 1]" ref="subjectChild" @isSubmit="getSubmit"></component>

data(){
  const num = (rule, value, callback) => {
    let num = /^\d+$/
    if(!value){
      return callback(new Error('数量不能为空'))
    }else if(!num.test(value)){
      return callback(new Error('数量必须为数字'))
    }else{
      callback()
    }
  }
  const price = (rule, value, callback) => {
    let num2 = /^\d+$/
    if(!value){
      return callback(new Error('单价不能为空'))
    }else if(!num2.test(value)){
      return callback(new Error('单价必须为数字'))
    }else{
      callback()
    }
  }
  return{
    // 验证
    apple:{
      num: '',
      price: '',
    },
    reg:{
      num: [
        { validator: num, trigger: 'blur' }
      ],
      price: [
        { validator: price, trigger: 'blur' }
      ]
    }
  }
// 验证
  submitForm(){
    this.$refs.apple.validate((valid) => {
      if(valid){
        this.$emit('isSubmit',["subject",true])
      }else{
        this.$emit('isSubmit',["subject",false])
        return false
      }
    })
  }

 // 获取子组件状态
  getSubmit(type){
    this.isRule = type[1]
  },
// 公共数据验证
  submitForm2(){
    // 如果选中了子组件
    if(this.changValue){
      this.$refs.subjectChild.submitForm()
    }
    let _this = this
    let p1 = new Promise((resolve, reject) => {
      _this.$refs.ruleForm.validate((valid) => {
        if(valid){
          resolve()
        }
      })
    })
    if(_this.isRule){
      Promise.all([p1]).then(() => {
        console.log('正确')
      })
      .catch(() => {
        console.log('错误')
      })
    }else{
      console.log('错误')
    }
  },