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>