在 select 上获取 v-select 文本

Question

我看到了一些关于 v-select 和插槽的文档，但我不太明白我是否可以将其应用于我的示例 codepen.

我只需要获取 selected text（不是值），然后在代码中的某处使用它：

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    state: {},
    selectedText: "",
    states: [
      { value: "a", text: "alpha" },
      { value: "b", text: "beta" },
      { value: "g", text: "gamma" }
    ]
  },
  methods: {
    change: (newValue) => {
      // do something with the text
      // "alpha", "beta", or "gama"
      console.log(newValue);
    }
  }
});

<link href="https://cdn.jsdelivr.net/npm/@mdi/font@4.x/css/materialdesignicons.min.css" rel="stylesheet"/>
<link href="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.css" rel="stylesheet"/>
<script src="https://cdn.jsdelivr.net/npm/babel-polyfill/dist/polyfill.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue@2.x/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.js"></script>
<div id="app">
  <v-app id="inspire">
    <v-container fluid>
      <label>my selected text is: {{state}}</label>
      <v-row align="center">
        <v-col cols="3">
          <v-select v-model="state" :items="states" @change="change" :text="selectedText"></v-select>
        </v-col>
      </v-row>
    </v-container>
  </v-app>
</div>

Answer 1

您需要将 return-object 属性添加到 <v-select>

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    state: null,
    selectedText: "",
    states: [
      { value: "a", text: "alpha" },
      { value: "b", text: "beta" },
      { value: "g", text: "gamma" }
    ]
  },
  methods: {
    change: (newValue) => {
      // do something with the text
      // "alpha", "beta", or "gama"
      console.log(newValue.text);
    }
  }
});

<link href="https://cdn.jsdelivr.net/npm/@mdi/font@4.x/css/materialdesignicons.min.css" rel="stylesheet"/>
<link href="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.css" rel="stylesheet"/>
<script src="https://cdn.jsdelivr.net/npm/babel-polyfill/dist/polyfill.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue@2.x/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.js"></script>
<div id="app">
  <v-app id="inspire">
    <v-container fluid>
      <label>my selected text is: {{state && state.text}}</label>
      <v-row align="center">
        <v-col cols="3">
          <v-select :items="states" v-model="state" @change="change" item-text="text" return-object></v-select>
        </v-col>
      </v-row>
    </v-container>
  </v-app>
</div>

编辑： 好的，根据您的方法，解决方案是使用国家代码在国家列表中找到合适的国家对象并进行设置。

解决方法如下：

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    country: "c",
    countries: [{
        code: "a",
        name: "Ameriga Fatela"
      },
      {
        code: "b",
        name: "Bolivia Grande"
      },
      {
        code: "c",
        name: "Comore Potentia"
      }
    ]
  },
  methods: {
    getCountryCode() {
      return "b"; // have no c.name here!
    },
    change() {
      var newCode = this.getCountryCode();
      // Since we were getting objects when changing options, we must also set objects 
      this.country = this.countries.filter(country => country.code === newCode)[0];
    }
  }
});

<link href="https://cdn.jsdelivr.net/npm/@mdi/font@4.x/css/materialdesignicons.min.css" rel="stylesheet" />
<link href="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/babel-polyfill/dist/polyfill.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue@2.x/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.js"></script>
<div id="app">
  <v-app>
    <v-container>
      <div>current code is &gt;{{country.code}}&lt;</div>
      <div>current name is &gt;{{country.name}}&lt;</div>
      <v-row>
        <v-col cols="12">
          <v-select v-model="country" :items="countries" item-text="name" item-value="code" return-object></v-select>
          <v-btn @click="change">change by script to 'b'</v-btn>
          </vcol>
      </v-row>
    </v-container>
  </v-app>
</div>

Answer 2

您的 states 对象同时包含 value 和 text 属性。如果您将 value 更改为 key，v-select 会识别更改并且您可以通过 this.state 访问 text 属性。像这样：

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    state: {},
    selectedText: "",
    states: [
      { key: "a", text: "alpha" },
      { key: "b", text: "beta" },
      { key: "g", text: "gamma" }
    ]
  },
  methods: {
    change: (newValue) => {
      // do something with the text
      // "alpha", "beta", or "gama"
      console.log(newValue); // Also returns text attribute instead of key
    }
  }
});

<div id="app">
  <v-app id="inspire">
    <v-container fluid>
      <label>my selected text is: {{state}}</label>
      <v-row align="center">
        <v-col cols="3">
          <v-select v-model="state" :items="states" @change="change"></v-select>
        </v-col>
      </v-row>
    </v-container>
  </v-app>
</div>

Answer 3

编辑： 我找到的最佳选择是对所选文本使用 computed 属性，而不更改当前代码（进入 FullPage 启动代码片段以正确查看输出后）：

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    countries: [
      { code: "a", name: "Ameriga Fatela" },
      { code: "b", name: "Bolivia Grande" },
      { code: "c", name: "Comore Potentia" }
    ],
    country: "b"
  },
  methods: {
    getCountryCode() {
      return "c"; // have no c.name here!
    },
    change() {
      this.country = this.getCountryCode();
    }
  },
  computed: {
    countryName() {
      return this.countries.find((c) => c.code === this.country).name;
    }
  }
});

<link href="https://cdn.jsdelivr.net/npm/@mdi/font@4.x/css/materialdesignicons.min.css" rel="stylesheet" />
<link href="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/babel-polyfill/dist/polyfill.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue@2.x/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.js"></script>
<div id="app">
  <v-app>
    <v-container>
      <div>current code is &gt;{{country}}&lt;</div>
      <div>current name is &gt;{{countryName}}&lt;</div>
      <v-row>
        <v-col cols="12">
          <v-select v-model="country" :items="countries" item-text="name" item-value="code"></v-select>
          <v-btn @click="change">change by script to '{{getCountryCode()}}'</v-btn>
          </vcol>
      </v-row>
    </v-container>
  </v-app>
</div>

另一个选项是（Codepen here）Anurag Srivastava的建议使用return-object，我返回了对象。但是，它有一些缺点，因为实际上我无法通过代码正确更改值：

new Vue({
  el: "#app",
  vuetify: new Vuetify(),
  data: {
    country: "c",
    countries: [
      { code: "a", name: "Ameriga Fatela" },
      { code: "b", name: "Bolivia Grande" },
      { code: "c", name: "Comore Potentia" }
    ]
  },
  methods: {
    getCountryCode() {
      return "b"; // have no c.name here!
    },
    change() {
      var newCode = this.getCountryCode();
      this.country = newCode;
    }
  }
});

<link href="https://cdn.jsdelivr.net/npm/@mdi/font@4.x/css/materialdesignicons.min.css" rel="stylesheet" />
<link href="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.css" rel="stylesheet" />
<script src="https://cdn.jsdelivr.net/npm/babel-polyfill/dist/polyfill.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue@2.x/dist/vue.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vuetify@2.2.20/dist/vuetify.min.js"></script>
<div id="app">
  <v-app>
    <v-container>
      <div>current code is &gt;{{country.code}}&lt;</div>
      <div>current name is &gt;{{country.name}}&lt;</div>
      <v-row>
        <v-col cols="12">
          <v-select v-model="country" :items="countries" item-text="name" item-value="code" return-object></v-select>
          <v-btn @click="change">change by script to 'b'</v-btn>
          </vcol>
      </v-row>
    </v-container>
  </v-app>
</div>

但是，在这两种情况下我们都应该重新计算国家名称。这是不好的。想象一下，要构建组合框，我们必须进行繁重的操作……每次都重新计算它非常耗时，而且确实不是最优的……

在 select 上获取 v-select 文本

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