son是father的子组件，father是grandfather的子组件。

1. 子组件向祖父组件传值

1.1 son组件

<son @click="clickson"/>
<script >
export default {
methods: {
    clickson (args) {
        this.$emit('clickfather', args) //args要传的参数
    }
}
}
</script>

1.2 father组件

<father >
    <son @clickson='clickfather' />
<father>
<script >
export default {
methods: {
    clickfather (args) {
        this.$emit('clickgrandfather', args) //args要传的参数
    }
}
}
</script>

1.3 grandfather组件

<grandfather >
    <father @clickfather='clickgrandfather'/>
<grandfather>
<script >
export default {
methods: {
    clickgrandfather () {
        console.log(args)//args要传的参数
    }
}
}
</script>

2. 祖父组件向子组件传值

1. 1 grandfather组件

<template>
  <div class="grandfather">
    <father :msg1="msg1" />
  </div>
</template>

<script>f
import father from './father'
export default {
  components: {father},
  data () {
    return {
      msg1: '疫情是6月1号解封？'
    }
  }
}
</script>

1.2 father组件

<template>
  <div class="father">
    <son :msg1="msg1" />
  </div>
</template>s

<script>
import son from './son'
export default {
  props: ['msg1'],
  components: {son},
}
</script>

1.3 son组件

<template>
<div class="son">
  <p>{{msg1}}</p>
</div>
</template>

<script>
export default {
  props: ['msg1']
}
</script>