1、概述
每个 Vue 实例都实现了事件接口，即：
- 使用
$on(eventName)监听事件 - 使用
$emit(eventName, optionalPayload)触发事件
2、示例一（未传递数据）
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>vue 父子通信过程（未传递数据）</title> </head> <body> <div id="root"> <div id="counter-event-example"> <p>{{ total }}</p> <button-counter v-on:increment="incrementTotal"></button-counter> <button-counter v-on:increment="incrementTotal"></button-counter> </div> </div> <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> <script type="text/javascript"> Vue.component('button-counter', { template: '<button v-on:click="incrementCounter">{{ counter }}</button>', data: function() { return { counter: 0 } }, methods: { incrementCounter: function() { this.counter += 1 this.$emit('increment') } }, }); new Vue({ el: '#counter-event-example', data: { total: 0 }, methods: { incrementTotal: function() { this.total += 1 } } }); </script> </body> </html>
3、示例二（传递数据）
<!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <meta http-equiv="X-UA-Compatible" content="ie=edge" /> <title>vue 父子通信过程（传递数据）</title> </head> <body> <div id="root"> <div id="message-event-example" class="demo"> <p v-for="msg in messages">{{ msg }}</p> <button-message v-on:message="handleMessage"></button-message> </div> </div> <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> <script type="text/javascript"> Vue.component('button-message', { template: `<div> <input type="text" v-model="message" /> <button v-on:click="handleSendMessage">Send</button> </div>`, data: function() { return { message: 'test message' } }, methods: { handleSendMessage: function() { this.$emit('message', { message: this.message }) } } }) new Vue({ el: '#message-event-example', data: { messages: [] }, methods: { handleMessage: function(payload) { this.messages.push(payload.message) } } }) </script> </body> </html>