Three commonly used value transfer methods in Vue

This article shares with you the three commonly used value transfer methods in Vue. It has certain reference value. Friends in need can refer to it.

1. Parent component passes value to child component:

Parent component:

        <template>
      <p>
        父组件:
        <input type="text" v-model="name">
        <br>
        <br>
        <!-- 引入子组件 -->
        <child :inputName="name"></child>
      </p>
    </template>
    <script>
      import child from './child'
      export default {
        components: {
          child
        },
        data () {
          return {
            name: ''
          }
        }
      }
    </script>

Child component:

    <template>
      <p>
        子组件:
        <span>{{inputName}}</span>
      </p>
    </template>
    <script>
      export default {
        // 接受父组件的值
        props: {
          inputName: String,
          required: true
        }
      }
    </script>

2. Child component passes value to parent component

Child component:

       <template>
          <p>
            子组件:
            <span>{{childValue}}</span>
            <!-- 定义一个子组件传值的方法 -->
            <input type="button" value="点击触发" @click="childClick">
          </p>
        </template>
        <script>
          export default {
            data () {
              return {
                childValue: '我是子组件的数据'
              }
            },
            methods: {
              childClick () {
                // childByValue是在父组件on监听的方法
                // 第二个参数this.childValue是需要传的值
                this.$emit('childByValue', this.childValue)
              }
            }
          }
        </script>

Parent component:

  <template>
  <p>
    父组件:
    <span>{{name}}</span>
    <br>
    <br>
    <!-- 引入子组件 定义一个on的方法监听子组件的状态-->
    <child v-on:childByValue="childByValue"></child>
  </p>
</template>
<script>
  import child from './child'
  export default {
    components: {
      child
    },
    data () {
      return {
        name: ''
      }
    },
    methods: {
      childByValue: function (childValue) {
        // childValue就是子组件传过来的值
        this.name = childValue
      }
    }
  }
</script>

3. Non-parent-child component passes value. (To transfer values ​​between non-parent and child components, you need to define a public public instance file bus.js as an intermediate warehouse to transfer values, otherwise the value transfer effect between routing components will not be achieved.)

Public bus .js

//bus.js
import Vue from 'vue'
export default new Vue()

Component A:

<template>
  <p>
    A组件:
    <span>{{elementValue}}</span>
    <input type="button" value="点击触发" @click="elementByValue">
  </p>
</template>
<script>
  // 引入公共的bug，来做为中间传达的工具
  import Bus from './bus.js'
  export default {
    data () {
      return {
        elementValue: 4
      }
    },
    methods: {
      elementByValue: function () {
        Bus.$emit('val', this.elementValue)
      }
    }
  }
</script>




组件B：
    <template>
      <p>
        B组件:
        <input type="button" value="点击触发" @click="getData">
        <span>{{name}}</span>
      </p>
    </template>
    <script>
      import Bus from './bus.js'
      export default {
        data () {
          return {
            name: 0
          }
        },
        mounted: function () {
          var vm = this
          // 用$on事件来接收参数
          Bus.$on('val', (data) => {
            console.log(data)
            vm.name = data
          })
        },
        methods: {
          getData: function () {
            this.name++
          }
        }
      }
    </script>

Related recommendations:

Detailed introduction to hook functions in Vue

Detailed analysis of Vue custom instructions and instruction definition functions (code)

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