父组件v-model绑定一个值
以下均为子组件
//模式一

model: {
    prop: 'listKey',
    event: 'change'
},
props: ['dataList', 'listKey'],//允许其他props
data: () => ({
    thisListKey: -1//防止本地直接修改props
}),
watch: {
    thisListKey() {
        this.$emit('change', this.thisListKey);//emit上面写的event
    },
    listKey() {
        this.thisListKey = this.listKey;//外部修改同步到内部
    }
}

//模式二

model: {
    prop: "selected",
    event: "change",
},
props: ["item", "selected"],
computed: {
    thisSelected: {
        get() {
            return this.selected;
        },
        set(e) {
            this.$emit("change", e);
        },
    },
},