vue中$emit的用法,父子组件传值及页面跳转之间传值

====== 一、父子组件传值========

1、父组件可以使用 props 把数据传给子组件。
2、子组件可以使用 $emit,让父组件监听到自定义事件 。

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; 

例如:子组件:

<template>
  <div class="train-city">
    <h3>父组件传给子组件的toCity:{{sendData}}</h3> 
    <br/><button @click='select(`大连`)'>点击此处将‘大连’发射给父组件</button>
  </div>
</template>
<script>
  export default {
    name:'trainCity',
    props:['sendData'], // 用来接收父组件传给子组件的数据
    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>

父组件:

<template>
    <div>
        <div>父组件的toCity{{toCity}}</div>
        <train-city @showCityName="updateCity" :sendData="toCity"></train-city>
    </div>
<template>
<script>
  import TrainCity from "./train-city";
  export default {
    name:'index',
    components: {TrainCity},
    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>

图一:点击之前的数据

图二:点击之后的数据

 

====== 二、页面跳转传值========

 

页面跳转传值:

pages/pre/pre.vue

<template>
    <view>
        <view>返回的数据为:</view>
        <view>id: {{testdata.id}}</view>
        <view>name: {{testdata.name}}</view>
        <button type="primary" @click="goNext">跳转到下一页面</button>
    </view>
</template>
 
<script>
    export default {
        data() {
            return {
                testdata: {
                    id: '',
                    name: ''
                }
            }
        },
        onShow() {
            let that = this
            uni.$on('updateData',function(data){
                that.testdata = data
                const params = 'id:'+data.id+', name:'+data.name;
                console.log('监听到事件来自 updateData ,携带参数为:' + params);
            })
        },
        methods: {
            goNext() {
                uni.navigateTo({
                    url: '/pages/next/next'
                })
            }
        }
    }
</script>
 
<style>
 
</style>

pages/next/next.vue

<template>
    <view>
        <button type="primary" @click="goBack">点击返回上一页</button>
    </view>
</template>
 
<script>
    export default {
        data() {
            return {
                mydata: {
                    id: 1,
                    name: 'test'
                }
            }
        },
        methods: {
            goBack() {
                uni.$emit('updateData', this.mydata)
                uni.navigateBack({
                    delta: 1
                })
            }
        }
    }
</script>
 
<style>
 
</style>

 

 

另一种页面传值方法(h5和小程序有区别),非页面传参类型:

pages/pre/pre.vue

<template>
    <view>
        <view>返回的数据为:</view>
        <view>id: {{testdata.id}}</view>
        <view>name: {{testdata.name}}</view>
        <button type="primary" @click="goNext">跳转到下一页面</button>
    </view>
</template>
 
<script>
    export default {
        data() {
            return {
                testdata: {
                    id: '',
                    name: ''
                }
            }
        },
        onShow() {
            let pages = getCurrentPages();
            let currPage = pages[pages.length - 1]; //当前页面
            let json = currPage.data.testdata;
            this.testdata = json;
        },
        methods: {
            goNext() {
                uni.navigateTo({
                    url: '/pages/next/next'
                })
            }
        }
    }
</script>
 
<style>
 
</style>

pages/next/next.vue

<template>
    <view>
        <button type="primary" @click="goBack">点击返回上一页</button>
    </view>
</template>
 
<script>
    export default {
        data() {
            return {
                mydata: {
                    id: 1,
                    name: 'test'
                }
            }
        },
        methods: {
            goBack() {
                var pages = getCurrentPages();
                var prevPage = pages[pages.length - 2];
                // #ifdef H5
                prevPage.$vm.testdata = this.mydata;
                // #endif
                // #ifdef MP-WEIXIN
                 prevPage.setData(this.mydata);
                // #endif
                uni.navigateBack({//返回
                    delta: 1
                })
            }
        }
    }
</script>
 
<style>
 
</style>

 

 

转 : https://blog.csdn.net/sllailcp/article/details/78595077

https://blog.csdn.net/qq2942713658/article/details/114581476

 

posted @ 2022-01-14 19:29  与f  阅读(2617)  评论(0编辑  收藏  举报