Vue.js在V模型中绑定数组

Question

I would like to bind v-model to an array of values

So i have

paymenttypes:[
 {label:'cheque', value:1},
 {label:'two', value:2}
]

pays:[],
created(){
   this.paymentmethods.forEach((value) => {
     this.pays.push({id:value.value, ref: '' , val: 0 })
   });
}

now on the template

  <div class="row saleTotal" v-for="(key, extrafieldsDetails) in paymentmethods">
    <div class="col-sm-4">
      <h5>{{extrafieldsDetails.label}}</h5>
    </div>
    <div class="col-sm-4">
      <input type="number" min="0" class="text-right form-control" v-model="pays[key].ref">
    </div>
  </div>

But am getting an error

cannot read property 'ref' of undefined 

What could be wrong? as the pays array has a object with a key of ref. Where am i going wrong?

Answer 1

I am assuming that your variables paymenttypes and paymentmethods are the same.

If so, your v-for binding is incorrect. You do not get key-value pairs out of paymentmethods because it is an array, not an object.

So, your v-for could be written as v-for="(item, index) in paymentmethods" where item is the array item from paymentmethods , and index is the index of item in paymentmethods .

Then you would need to replace the property accessors as follows:

• {{item.label}} instead of {{extrafieldsDetails.label}}

• pays[index].ref instead of pays[key].ref

 var app = new Vue({ el: "#app", data: { paymentmethods:[ {label:'cheque', value:1}, {label:'two', value:2} ], pays:[] }, created(){ this.paymentmethods.forEach((value) => { this.pays.push({id:value.value, ref: '' , val: 0 }) }); console.log(this.pays); } }); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.3/vue.min.js"></script> <div id="app"> <div class="row saleTotal" v-for="(item, index) in paymentmethods"> <div class="col-sm-4"> <h5>{{item.label}}</h5> </div> <div class="col-sm-4"> <input type="number" min="0" class="text-right form-control" v-model="pays[index].ref"> </div> </div> </div>