Question

如何选择带有select的第一个项目（在vue.js中）？

<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>

Answer 1

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圈内会自动提供v-for。

在Vue 2中，您需要为索引显式声明一个变量。

Answer 2

在您的json中，我找不到location.id。而您的"locations"是obj。但是，如果"locations"是arr，则可以使用以下代码：

  <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selectedLocation (v-model)。

Answer 3

与@J相似。布鲁尼的答案虽然对你来说似乎不起作用。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>

Answer 4

您可以在select中使用v-model，当您加载列表时，将第一个值传递给模型变量，并且始终会选择第一个值

Answer 5

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

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

您只需要将v模型ride.location_id更新为vuejs created(){}或mounted(){}方法

选择始终第一个值选择vue.js

5 个答案: