vue3父组件修改子组件的方法或者修改子组件的值

子组件使用defineExpose暴露出去

子组件testIndex.vue

<template>
<div>
    {{num}}
</div>
</template>
<script setup>
    import {ref} from "vue";

    const count= ref(0);
    const num = ref(0);
     function childMethod() {
        console.log('我是子组件');
        num.value+=5
    }
    
    defineExpose({ 
        count,
        num,
        childMethod
    });
</script>

父组件

<template>
<el-button @click="test">点击改变父组件的值和方法</el-button>
<TestIndex ref="V"></TestIndex>
</tempalte>
<script setup>
	import { ref } from "vue";
	import TestIndex from "./testIndex.vue"
		const V=ref(null)
		const test=()=>{
        const {count} = V.value
            V.value.count++;
			V.value.childMethod();
		}
<script>