assign value to select in methods in vuejs?

<a-radio-group
  @change="changeName"
  v-decorator="[
                'name',
                { initialValue: 'light' },
                ]"
>
  <a-radio value="iphone">Iphone</a-radio>
  <a-radio value="samsung">Samsung</a-radio>
</a-radio-group>
   

<a-form-item label="Value" :colon="false">
  <a-select placeholder="Select a value">
    <a-select-option></a-select-option>
  </a-select>
</a-form-item>

methods: {
  changeName(event) {
    var value = event.target.value;
    if (value == 'iphone') {
      // I want to assign the select-option the value : 
      //<a-select-option value="ip12">Iphone 12</a-select-option>
      // <a-select-option value="ip13">Iphone 13</a-select-option>
    } else {
      //<a-select-option value="ss10">Samsung note 10</a-select-option>
      // <a-select-option value="ss9">Samsung note 9</a-select-option>
    }
  }
}

How do I change the <a-select-option>s when I select a radio button?

Answer

You can compute the <a-select>‘s options based on the <a-radio-group>‘s value.

1. Instead of the change-event handler, use a v-model directive on the <a-radio-group> to store the selected brand, and on the <a-select> to store the selected phone:

   <template>
     <a-radio-group v-model="selectedBrand">
       <!-- brands -->
     </a-radio-group>
   
     <a-select placeholder="Select a value" v-model="selectedPhone">
       <!-- phone options -->
     </a-select>
   </template>
   
   <script>
   export default {
     data () {
       return {
         selectedBrand: '',
         selectedPhone: '',
       }
     }
   }
   </script>
   

2. Add a computed property for the options to show based on the selected brand:

   const PHONE_OPTIONS = {
     iphone: [
       { value: 'iph12', label: 'Iphone 12' },
       { value: 'iph13', label: 'Iphone 13' },
     ],
     samsung: [
       { value: 'ss10', label: 'Samsung Note 10' },
       { value: 'ss9', label: 'Samsung Note 9' },
     ],
   }
   
   export default {
     computed: {
       phoneOptions() {
         return PHONE_OPTIONS[this.selectedBrand]
       },
     },
   }
   

3. Use a watcher on the phone options to automatically select the first one.

   export default {
     watch: {
       phoneOptions(value) {
         this.selectedPhone = value?.[0].value
       },
     },
   }
   

4. Render the phone options:

   <a-select-option v-for="opt in phoneOptions" :key="opt.value" :value="opt.value">
     {{ opt.label }}
   </a-select-option>
   

demo