vue2.0 element-ui中el-select选择器无法显示选中的内容(解决方法)

<template>
 <div>
  <div class="row" v-for="RowItem in rows">
   <div class="col" v-for="colItem in RowItem.configVos">
    <el-select v-model="formData[colItem.paramCode]" :class="getModel(colItem.paramCode)" @change=" Change(colItem.paramCode,formData[colItem.paramCode])">
     <el-option v-for="option in colItem.configOptions" :label="option.optionCode" 
      :value="option.optionValue" >
     </el-option>
  </el-select>
   </div>  
  </div>  
 </div> 
</template>
< >
 import axios from 'axios';
 export default {
  data() {
   return {
    groupItem:{},
    formData:{},
    rows:'',
    cols:''
   }
  },
  watch:{
  },
  methods:{   
   getfordata:function(){
    var _this = this;
    axios.get('../json/selectdata.json')
    .then(function(res){
     _this.groupItem = res.data;
     var row = _this.groupItem[0].rowData;
     _this.rows = row;    
     for(var i=0;i<row.length;i++){
      var col = row[i].configVos;     
      for(var j=0;j<col.length;j++){ 
       var key = col[j];       
        _this.formData[key.paramCode] = '';    
      }
     }     
    })
   },
    Change:function(key,val){
    console.log(val);
   },
   getModel(model) {
    console.log(model);
   }
  },
  created:function(){
   this.getfordata();
  }
 }
</ >
<style scoped>
 .col{
  float:left;
 }
 .row{
  width:800px;
  height:100px;
 }
</style>

[
 {
 "groupName": "抽数转换",
 "rowData": [
  {
  "configVos": [
   {
   "configOptions": [
    {
    "id": "D",
    "optionCode": "否",
    "optionValue": "0",
    "paramId": "4"
    },
    {
    "id": "5",
    "optionCode": "是",
    "optionValue": "1",
    "paramId": "4"
    }
   ],
   "id": "4E",
   "paramCode": "isView",
   "paramValue": "0"
   },
   {
   "configOptions": [
    {
    "id": "4",
    "optionCode": "老版本",
    "optionValue": "0",
    "paramId": "4"
    },
    {
    "id": "4",
    "optionCode": "新版本",
    "optionValue": "1",
    "paramId": "44"
    }
   ],
   "id": "24",
   "paramCode": "isDeleteCbnd",
   "paramValue": "1"
   }
  ]
  },
  {
  "configVos": [
   {
   "configOptions": [
    {
    "id": "EF",
    "optionCode": "估值2.5",
    "optionValue": "0",
    "paramId": "1"
    },
    {
    "id": "8B",
    "optionCode": "估值2.5+qd",
    "optionValue": "1",
    "paramId": "131"
    },
    {
    "id": "06",
    "optionCode": "恒生2.5",
    "optionValue": "2",
    "paramId": "1"
    },
    {
    "id": "25BF",
    "optionCode": "估值4.5",
    "optionValue": "3",
    "paramId": "31"
    }
   ],
   "id": "31",
   "paramCode": "converType",
   "paramValue": "0"
   },
   {
   "configOptions": [
    {
    "id": "1366",
    "optionCode": "万德",
    "optionValue": "0",
    "paramId": "98"
    },
    {
    "id": "EC",
    "optionCode": "聚源",
    "optionValue": "1",
    "paramId": "8"
    }
   ],
   "id": "91F8",
   "paramCode": "zxDataSource",
   "paramValue": "0"
   }
  ]
  },
  {
  "configVos": [
   {
   "configOptions": [
    {
    "id": "CD",
    "optionCode": "期货占用",
    "optionValue": "HS",
    "paramId": "5C"
    },
    {
    "id": "91508011",
    "optionCode": "其它",
    "optionValue": "YYS",
    "paramId": "91C"
    }
   ],
   "id": "5C",
   "paramCode": "derivativeDataSource",
   "paramValue": "HS"   
   }
  ]
  }
 ]
 }
]