vue2.0父子组件间传递数据的方法

<template>
 <child :child-msg="msg" @ok="event"></child>
</template>
<script>
import child from './child.vue';
export default {
 data(){
 return{
 msg:'hello worldgogo'
 }
 },
 components:{
 child
 },
 methods:{
 event(val){
 console.log(val);
 }
 }
}
</script>
<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
</style>

<template>
 <p>{{childMsghello}}</p>
</template>
<script>
export default {
 props: ['childMsg'],
 data(){
 return{
 childMsghello:this.childMsg+'this is child'
 }
 },
 created(){
 //自定义事件，并且给监听此事件的回调函数的值设为200
 this.$emit('ok','200');
 }
}
</script>
<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
</style>