如何理解Vue的v-model指令的使用方法

2020-11-27 来源：爱go旅游网

本文主要讲解v-model指令，主要包括HTML元素的v-model和组件上的v-model两种，用四个简单的案例介绍v-model的使用。

案例一：HTML元素的v-model -输入框(text)

<!DOCTYPE html>
 <html lang="en">
 <head>
 <meta charset="UTF-8">
 <title>v-model指令</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
 </head>
 <body>
 <div id="app4">
 {{price}}<br>
 <input v-model="price"><!-- 下行注释的语法糖 -->
 <!-- <input :value="price" @input="price = $event.target.value"> -->
 </div>
 <script>
 new Vue({
 el: '#app4',
 data: {
 price: '20'
 }
 });
 </script>
 </body>
</html>

案例二：定制组件的v-model - 输入框(text)

<!DOCTYPE html>
 <html lang="en">
 <head>
 <meta charset="UTF-8">
 <title>v-model指令</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
 </head>
 <body>
 <div id="app3">
 {{price}}
 <my-input v-model="price"></my-input><!-- 下行注释的语法糖 -->
 <!-- <my-input :value="price" @input="val => {price = val}"></my-input> -->
 </div>
 <script>
 Vue.component('my-input', {
 template: '<div></span><input type="text" ref="input" :value="value" @input="doThis"/></div>',
 props: {
 value: String
 },
 methods: {
 doThis() {
 this.$emit('input', this.$refs.input.value);
 }
 }
 });
 new Vue({
 el: '#app3',
 data: {
 price: '10'
 }
 });
 </script>
 </body>
</html>

案例三：定制组件的v-model - 复选框(checkbox) - 2.2.0 新增

 <!DOCTYPE html>
 <html lang="en">
 <head>
 <meta charset="UTF-8">
 <title>v-model指令</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
 </head>
 <body>
 <div id="app2">
 {{fruit}}<!-- 观测数据变化 -->
 <my-checkbox v-model="fruit.apple" value="apple"></my-checkbox><!-- 下行注释的语法糖 -->
 <!-- <my-checkbox :checked="fruit.apple" @change="val => {fruit.apple = val}" value="apple"></my-checkbox> -->
 
 <my-checkbox v-model="fruit.peach" value="peach"></my-checkbox><!-- 下行注释的语法糖 -->
 <!-- <my-checkbox :checked="fruit.peach" @change="val => {fruit.peach = val}" value="peach"></my-checkbox> -->
 </div>
 <script>
 Vue.component('my-checkbox', {
 template: '<div><span>{{value}}</span><input type="checkbox" :checked="checked" @change="doThis" :value="value"/></div>',
 model: {
 prop: 'checked',
 event: 'change'
 },
 props: {
 checked: Boolean,
 value: String
 },
 methods: {
 doThis() {
 this.$emit('change', !this.checked);
 }
 }
 });
 new Vue({
 el: '#app2',
 data: {
 fruit: {//数据
 apple: true,
 peach: false
 }
 }
 });
 </script>
 </body>
 </html>

案例四：定制组件的v-model - 单选按钮(radio) -2.2.0 新增

<!DOCTYPE html>

<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>v-model指令</title>
 <script src="https://cdn.bootcss.com/vue/2.3.4/vue.js"></script>
</head>
<body>
 <div id="app">
 {{fruit}}<!-- 观测数据变化 -->
 <my-radio v-model="fruit" value="apple" name="myFruit"></my-radio><!-- 下行注释的语法糖 -->
 <!-- <my-radio :checked="fruit" @change="val => {fruit = val}" value="apple"></my-radio> -->
 
 <my-radio v-model="fruit" value="peach" name="myFruit"></my-radio><!-- 下行注释的语法糖 -->
 <!-- <my-radio :checked="fruit" @change="val => {fruit = val}" value="peach"></my-radio> -->
 </div>
 <script>
 Vue.component('my-radio', {
 template: '<div><span>{{value}}</span><input :name="name" type="radio" ref="radio" :checked="checked===value" @change="doThis" :value="value"/></div>',
 model: {
 prop: 'checked',
 event: 'change'
 },
 props: {
 checked: String,
 value: String,
 name: String
 },
 methods: {
 doThis() {
 this.$emit('change', this.$refs.radio.value);
 }
 }
 });
 new Vue({
 el: '#app',
 data: {
 fruit: 'peach'//数据
 }
 });
 </script>
</body>
</html>

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如何理解Vue的v-model指令的使用方法