vue3组件通信的方式总结及实例用法

vue3组件通信的方式总结及实例用法

vue3组件通信方式为以下几种

  • props
  • $emit
  • $expose / ref
  • $attrs
  • v-model
  • provide / inject
  • Vuex
  • mitt

props

<child :msg2="msg2" />
<script setup>
    const props = defineProps({
        // 写法一
        msg2:String
        // 写法二
        msg2:{
            type:String,
            default:""
        }
    })
    console.log(props) // {msg2:"这是传级子组件的信息2"}
</script>

$emit

//Child.vue
<template>
    // 写法一
    <div @click="emit("myclick")">按钮</div>
    // 写法二
    <div @click="handleClick">按钮</div>
</template>
<script setup>
    // 方法一
    const emit = defineEmits(["myClick"],["myClick2"])
    // 方法二
    const handleClick = () => {
        emit("myClick","这是发送给父组件的信息");
     }
      
     // 方法二 不适用于vue3.2,使用的useContext()已经舍弃
     import { useContext } from "vue"
     const { emit } = useContext()
     const handleClick = () => { 
      emit("myClick","这是发送给父组件的信息"   
     }
</script>
 
// Parent.vue响应
<template>
    <child @myClick="onMyClick"></child>
</template>
<script setup>
    import child from "./child.vue"
    import onMychilk = (msg) => {
        console.log(msg) // 父组件收到的信息 
    }
</script>

expose / ref

父组件获取子组件的属性或者调用子组件方法

<script setup>
    // 方法一:useContext() vue3.2 之后已经舍弃
    import { useContext } from "vue"
    const ctx = useContext()
    // 对外暴露属性方法等都可以
    ctx.expose({
        childName: "这是子组建的属性",
        someMethod(){
        console.log("这是子组件的方法")
        }
    })
</script>
 
// Parent.vue 注意 ref="comp"
<template>
    <child ref="comp"></child>
    <button @click="handleClick">按钮</button>
</template>
<script>
    import child from "./child.vue"
    import { ref } from "vue" 
    const comp = ref(null)
    const handleClick = () => {
        console.log(comp.value.childName)
        comp.value.someMethod() // 调用子组件对外暴露的方法
    }
</script>

attts

attrs:包含父作用域除class和style除外的非props属性集合

// 父组件
<child :msg1="msg1" :msg2="msg2" title="3333"></child>
<script setup>
    import child from "./child.vue"
    import { ref,reactive } from "vue
    const msg1 = ref("111")
    const msg2 = ref("222")
</script>
 
// 子组件
<script setup>
    import { defineProps,useContext,useAttars } from "vue"
    const props = defineProps({
        msg1: String
    })
     
    // 方法1
    const ctx = useContext()
    console.log(ctx.attars) // {msg2:"222",title:"333"}
     
    // 方法2 
    const attrs = useAttars()
    console.log(attars)  // {msg2:"2222",title:"3333"}
</script>

v-model

可以支持多个数据双向绑定

<child v-model:key="key" v-modle:value="value" />
<script>
    import child from "./child.vue"
    import { ref,reactive } from "vue"
    const key = ref("111")
    const value = ref("222")
</script>
 
//子组件
<template>
   <button @click="handleClick"></button>
</template>
<script setup>
    // 方法一  v3.2 已被移除
    import { useContext } from "vue"
    const { emit } = useContext()
     
    // 方法二
    import { defineEmits } from "vue"
    const emit = defineEmits(["key","value"])
     
    //用法
    const handleClick = () => {
        emit("update:key","新的key")
        emit("update:value","新的value")
    }
</script>

provide / inject

provide/inject为依赖注入 provide:可以让我们指定想要提供给后代组件的数据 inject:在任何后代组件中接受想要添加在这个组件上的数据,不管组件嵌套多深都可以直接拿来用

// 父组件
<script setup>
    import { provide } from "vue"
    const name = provide("name")
    console.log("name","沐华")
</script>
//子组件
<script setup>
    import { inject } from "vue"
    const name = inject("name")
    console.log(name) //木华
</script>

Vuex

//store/index.js
import { createStore } from "vuex"
export default createStore({
    state:{count:1},
    getters:{
        getCount:state=>state.count
    },
    mutations:{
        add(state){
            state.count++
        }
    }
   })
 // main.js
 import { createApp } from "vue"
 import APP from "./App.vue"
 import store from "./store"
 createApp(APP).use(store).mount("#app")
  
 // 直接使用
 <template>
     <div>
         {{ $store.state.count }}
     </div>
     <button @click="$store.commit("add")">
     </button>
 </template>
  
 // 获取
 <script setup>
     import { useStore,computed } from "vuex"
     const store = useStore()
     console.log(store.state.count)
      
     const count = computed (()=>store.state.count)
     console.log(count)
 </script>

mitt

Vue3中已经没有了EventBus跨组件通信,替代方案mitt.js,但原理方式EventBus是一样的
安装方式 npm i mitt -S

封装

mitt.js
import mitt from "mitt"
const mitt = mitt()
export default mitt

组件之间使用

// 组件A 
<script setup>
    import mitt from "./mitt"
    const handleClick = () => {
        mitt.emit("handleChange")
    }
</script>
// 组件B 
<script setup>
import mitt from "./mitt"
import { onUnmounted } from "vue"
const someMethod = () => {...}
mitt.on("handleChange",someMethod)
onUnmounted(()=>{
    mitt.off("handleChange",someMethod)
})
</script>

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