What are the uses of $emit in vue?-JS Tutorial-php.cn

What are the uses of $emit in vue?

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Release： 2018-04-28 14:23:35

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This time I will show you how to use $emit in vue, and what notesare when using $emit in vue. The following is a practical case, let's take a look.

1. Parent components can use props to pass data to child components.

2. Subcomponents can use $emit to trigger custom events of parent components.

vm.$emit( event, arg ) //触发当前实例上的事件
vm.$on( event, fn );//监听event事件后运行 fn；

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For example: Child component:

<template>  
 <p class="train-city">  
  <span @click=&#39;select(`大连`)&#39;>大连</span>  
 </p>  
</template>  
<script>  
export default {  
 name:'trainCity',  
 methods:{  
  select(val) {  
   let data = {  
    cityname: val  
   };  
   this.$emit('showCityName',data);//select事件触发后，自动触发showCityName事件  
  }  
 }  
}  
</script>

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Parent component:

<template>  
  <trainCity @showCityName="updateCity" :index="goOrtoCity"></trainCity> //监听子组件的showCityName事件。  
<template>  
<script>  
export default {  
 name:'index',  
 data () {  
  return {  
   toCity:"北京"  
  }  
 }  
 methods:{  
  updateCity(data){//触发子组件城市选择-选择城市的事件   
   this.toCity = data.cityname;//改变了父组件的值  
   console.log('toCity:'+this.toCity)     
  }  
 }  
}  
</script>

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The result is:

toCity: Dalian

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!