1. What are the communication methods of Vue2.x components?
1-1 Parent-child component communication
- father -> child props; child (emit) -> father (on)
- Get the parent-child component instance parent/parent / parent/children For example: write directly in the methods method of the child component: this.$parent.show()//show is the method defined in the parent component
- Ref (if used on a normal DOM element, the reference points to the DOM element; if used on a sub-component, the reference points to the component instance), such as mounting one on the label of the imported sub-component: ref="comA" , and then in the method or the data of the subcomponent, this.$refs.comA.titles
- Provide and inject are not officially recommended, but they are commonly used when writing component libraries. Provide variables in ancestor components, and then inject variables in descendant components through inject
1-2 Brother component communication
- Event Bus implements cross-component communication: Vue.prototype.$bus = new Vue
- Vuex
1-3 Cross-level component communication
- Vuex
- attrs,listeners
- Provide、inject
1-4 use
1. Parent and child props, on
// Subassembly
<template>
<header>
<h1 @click="changeTitle">{
{title}}</h1>//绑定一个点击事件
</header>
</template>
<script>
export default {
data() {
return {
title:"Vue.js Demo"
}
},
methods:{
changeTitle() {
this.$emit("titleChanged","子向父组件传值");//自定义事件 传递值“子向父组件传值”
}
}
}
</script>
// parent component
<template>
<div id="app">
<Header @titleChanged="updateTitle" ></Header>//与子组件titleChanged自定义事件保持一致
<h2>{
{title}}</h2>
</div>
</template>
<script>
import Header from "./Header"
export default {
data(){
return{
title:"传递的是一个值"
}
},
methods:{
updateTitle(e){ //声明这个函数
this.title = e;
}
},
components:{
Header
}
}
</script>
2. parent / $children与 ref
// A child component
export default {
data () {
return {
title: 'a组件'
}
},
methods: {
sayHello () {
alert('Hello');
}
}
}
// parent component
<template>
<A ref="comA"></A>
</template>
<script>
export default {
mounted () {
const comA = this.$refs.comA;
console.log(comA.title); // a组件
comA.sayHello(); // 弹窗
}
}
</script>
3.attrs，listeners
attrs: Contains all (and obtains) attribute bindings 父作用域in (except class and style). When a component does not declare any props, all parent scope bindings (except class and style) will be included here, and internal components can be passed in via v-bind="$attrs". Usually used in conjunction with the inheritAttrs option.不被 prop识别
listeners: : Contains the v-on event listeners in the parent scope (without the .native decorator). It can be passed to internal components via v-on="$listeners"
// index.view
<template>
<div>
<h2>宇六岁呀</h2>
<child-com1 :foo="foo" :boo="boo" :coo="coo" :doo="doo" title="前端"></child-com1>
</div>
</template>
<script>
const childCom1 = () => import("./childCom1.vue");
export default {
components: { childCom1 },
data() {
return {
foo: "Javascript",
boo: "Html",
coo: "CSS",
doo: "Vue"
};
}
};
</script>
// childCom1.view
<template class="border">
<div>
<p>foo: {
{ foo }}</p>
<p>childCom1的$attrs: {
{ $attrs }}</p>
<child-com2 v-bind="$attrs"></child-com2>
</div>
</template>
<script>
const childCom2 = () => import("./childCom2.vue");
export default {
components: {
childCom2
},
inheritAttrs: false, // 可以关闭自动挂载到组件根元素上的没有在props声明的属性
props: {
foo: String // foo作为props属性绑定
},
created() {
console.log(this.$attrs); // 父组件中的属性，且不在当前组件props中的属性。{ "boo": "Html", "coo": "CSS", "doo": "Vue", "title": "前端工匠" }
}
};
</script>
// childCom2.vue
<template>
<div class="border">
<p>boo: {
{ boo }}</p>
<p>childCom2: {
{ $attrs }}</p>
<child-com3 v-bind="$attrs"></child-com3>
</div>
</template>
<script>
const childCom3 = () => import("./childCom3.vue");
export default {
components: {
childCom3
},
inheritAttrs: false,
props: {
boo: String
},
created() {
console.log(this.$attrs); // / 父组件中的属性，且不在当前组件props中的属性。{"coo": "CSS", "doo": "Vue", "title": "前端工匠" }
}
};
</script>
// childCom3.vue
<template>
<div class="border">
<p>childCom3: {
{ $attrs }}</p>
</div>
</template>
<script>
export default {
props: {
coo: String,
title: String
}
};
</script>
4. Use of Provide and inject:
parent component
<template>
<div id="app">
</div>
</template>
<script>
export default {
data () {
return {
datas: [
{
id: 1,
label: '产品一'
}
]
}
},
provide {
return {
datas: this.datas
}
}
}
</script>
Subassembly
<template>
<div>
<ul>
<li v-for="(item, index) in datas" :key="index">
{
{ item.label }}
</li>
</ul>
</div>
</template>
<script>
export default {
inject: ['datas']
}
</script>