始终选择第一个值Select vue.js

Select always first value select vue.js

本文关键字：Select vue js 第一个 选择      更新时间：2023-09-26

如何总是用select(在vue.js中(选择第一个项目？

<div class="ride-item-content">
  <select v-model="ride.location_id">
    <option v-for="location in locations" v-bind:value="location.id">
      {{ location.from }} - {{ location.to }}
    </option>
  </select>
</div>

json

{
  "locations": {
    "total": 2,
    "per_page": 20,
    "current_page": 1,
    "last_page": 1,
    "next_page_url": null,
    "prev_page_url": null,
    "from": 1,
    "to": 2,
    "data": [
      {
        "id": 1,
        "user_id": 1,
        "description": "sdg",
        "from": "asdf",
        "to": "asdf",
        "kmz": "12",
        "kmp": "13",
        "time": 0,
        "hour": 0,
        "maps": "www.blablabla.nl",
        "created_at": null,
        "updated_at": null
      },
      {
        "id": 2,
        "user_id": 1,
        "description": "asdf",
        "from": "asdf",
        "to": "asdf",
        "kmz": "3",
        "kmp": "1",
        "time": 1,
        "hour": 0,
        "maps": "www.test.nl",
        "created_at": null,
        "updated_at": null
      }
    ]
  }
}

--编辑--

<div class="ride-item-content">
  <select v-model="ride.location_id">
    <option v-for="location in locations" v-bind:selected="$index === 0 ? 'selected' : false">
      {{ location.from }} - {{ location.to }}
    </option>
  </select>
</div>

VueJS 1:

<option v-for="location in locations" v-bind:value="location.id" v-bind:selected="$index === 0 ? 'selected' : false">
  {{ location.from }} - {{ location.to }}
</option>

VueJS 2:

<option v-for="(location, index) in locations" v-bind:value="location.id" v-bind:selected="index === 0">
  {{ location.from }} - {{ location.to }}
</option>

在Vue 1中，$index在v-for循环中自动可用。

在Vue 2中，您需要显式地为索引声明一个变量。

在您的json中，我找不到location.id。你的"locations"是obj。但如果"locations"是arr，你可以使用这个：

  <select v-model="selectedLocation">
    <option v-for="location in locations" :key="location.id" :value=location.id>
      {{ location.somekey }}
    </option>
  </select>

数据中-

selectedLocation: this.locations.length ? this.locations[0].id : ''

它可以工作，因为您的选择取决于选定的位置(v-model)。

您可以在选择中使用v-model，当您加载列表时，将第一个值传递给模型变量，并且总是会选择第一个值

created(){
    if(this.locations) {
        this.ride.location_id = this.locations[0].id
    }
}

工作示例jsfidelle链接https://jsfiddle.net/Rashid_Bukhari/q2ro6pz1/20/

您只需要将您的v-model ride.location_id更新为vuejs created(){}或mounted(){}方法

类似于@J。布鲁尼的回答，尽管这似乎对你不起作用。试试这个：

<option v-for="location in locations" v-bind:value="location.id" v-bind:selected="$index === 0 ? true : false">
    {{ location.from }} - {{ location.to }}
</option>
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