Vue中父组件向子组件传递数据的几种方法

//子组件 
<template>
    <div @click="changeName('YYY')">{{name}}</div>
</template>
<script>
export default{
    props:['name'],//or props:{name:{type:String,default:''}}
    methods:{
        //不能在子组件修改props数据，应触发事件让父组件处理
        changeName(newName){
            this.$emit('changeName',newName)
        }
    }
}
</script>
 
//父组件
<template>
    <div>
        <child-comp :name="name" @changeName="changeName"></child-comp>
    </div>
</template>
<script>
    import childComp from 'path'
    export default{
        data(){
            return {name:'XXX'}
        },
        components:{
            childComp
        },
        methods:{
            changeName(newName){
                this.name = newName;
            }
        }
    }
</scritp>

//子组件 
<template>
    <div>{{parentMsg}}</div>
</template>
<script>
export default{
    data(){
        return {
            parentMsg:''
        }
    },
    methods:{
        getMsg(msg){
            this.parentMsg = msg;
        }
    }
}
</script>
 
//父组件
<template>
    <div>
        <child-comp ref="child"></child-comp>
        <button @click="sendMsg">SEND MESSAGE</button>
    </div>
</template>
<script>
    import childComp from 'path'
    export default{
        components:{
            childComp
        },
        methods:{
            sendMsg(){
                this.$refs.child.getMsg('Parent Message');
            }
        }
    }
</scritp>

//child
<template>
    <div>{{appName}}</div>
</template>
<script>
export default{
    inject:['appName']
}
</script>
 
// root 
export default{
    data(){
        return {
            appName:'Test'
        }
    },
    provide:['appName']
}