How to communicate between Vue parent and child components? (with examples)

vueHow to communicate between parent and child components? The following article will introduce to you how the parent component passes data to the child component, and the child component passes the data to the parent component. I hope it will be helpful to you!

The variables and data in each component are independent. What should we do if another component wants to access the data in another component?

How to solve the communication between components?

Solution:

You can use the parent component to pass data to the child component, and you can also use the child component to pass data to the parent component. In short, it is passed down from father to son, and from son to father. (Learning video sharing: vue video tutorial)

Let’s talk in detail about how the parent component passes data to the child component.

father-to-child

---

Theory: If a component A introduces and uses another component B, then component A is the parent component and component B is Subassembly.

Implementation process:

   1.在父组件中引入子组件、注册子组件、使用子组件  
   2.在父组件中的子组件标签上自定义一个属性 左边是定义的名称，右边是父组件中的数据 例如
   <MyCon :list="list" />
   3.在子组件中用prpos接收父组件传来的数据 例如：prpos:[&#39;list&#39;]  注意这里面的名称必须要和父组件
   定义的名称一致才能可以。

Principle illustration

Parent component Footer.vue

Customize a property on the child component label in the parent component

<template>
  <div>
    <h1>父组件传子组件</h1>
    <!-- 使用组件   自定义属性 -->
    <MyCon :name="name" :age="age" />
  </div>
</template>
<script>
// 引入组件 --> 创建组件 -->  使用组件
// 引入组件
import MyCon from "./MyCon.vue";
export default {
   //  创建组件 
  components: { MyCon },
  // 数据
  data() {
    return {
      name: "张三",
      age: 38,
    };
  },
};
</script>

Child component MyCon.vue

Use prpos in the child component to receive data from the parent component

<template>
  <div>
    <h2>子组件</h2>
     // 直接在标签中使用
    <p>{{ name }} {{ age }}</p>
    <button @click="fn">点击修改props的值</button>
  </div>
</template>
<script>
export default {
  // 子组件接收父组件传来的数据
  props: ["name", "age"],
  methods: {
    fn() {
      this.name = "傻逼谭磊";
      this.age = 20
    },
  },
};
</script>

The small case uses parent-to-child transmission

Parent component App.vue

<template>
  <div style="border: 1px solid #ccc; margin: 5px; padding: 5px">
    <h1>父组件</h1>
    <!-- 1. 父传。自定义属性 -->
    <MyProduct
      v-for="item in list"
      :key="item.id"
      :price="item.proprice"
      :info="item.info"
      :goodname="item.proname"
    />
  </div>
</template>

<script>
// 导入->注册->使用
import MyProduct from "./MyProduct.vue";
export default {
  data() {
    return {
      list: [
        {
          id: 1,
          proname: "超级好吃的棒棒糖",
          proprice: 18.8,
          info: "开业大酬宾, 全场8折",
        },
        {
          id: 2,
          proname: "超级好吃的大鸡腿",
          proprice: 34.2,
          info: "好吃不腻, 快来买啊",
        },
        {
          id: 3,
          proname: "超级无敌的冰激凌",
          proprice: 14.2,
          info: "炎热的夏天, 来个冰激凌了",
        },
      ],
    };
  },
  components: { MyProduct },
};
</script>

<style>
</style>

Child component MyProduct.vue

<template>
  <div style="border: 1px solid #ccc; margin: 5px; padding: 5px">
    <h2>标题： {{ goodname }}</h2>
    <p>价格: {{ price }}元</p>
    <p>{{ info }}</p>
  </div>
</template>

<script>
export default {
  props: ["goodname", "price", "info"],
};
</script>

<style>
</style>

Effect display

Son passes on to father

---

Implementation process

     1.在父组件中引入子组件、注册子组件、使用子组件  
     2.在父组件的子组件标签上加一个事件监听 例如:  <MyCon @abc="fn" />
     3.在子组件中触发这个自定义的监听事件。例如:this.$emit("abc",参数)

Principle illustration

Parent component App.vue

Add an event listener on the sub-component label of the parent component and receive it with formal parameters Data

<template>
  <div>
    <h1>父组件</h1>
    <!-- 1.添加事件监听 -->
    <!-- 当子组件发生了abc事件要执行fn函数 -->
    <MyCon @abc="fn" />
  </div>
</template>
<script>
// 引入子组件
import MyCon from "./MyCon.vue";
export default {
  methods: {
  // 形参接收
    fn(obj) {
      // 打印查看有没有获取到
      console.log("fn发生了abc事件", obj);
    },
  },
  components: { MyCon },
};
</script>

Subcomponent MyCon.vue

Trigger this custom listening event in the subcomponent

<template>
  <div>
    <h2>子组件</h2>
    <button @click="ConFn">子传父</button>
  </div>
</template>
<script>
export default {
  methods: {
    ConFn() {
      console.log("子组件click");
      // 2.触发abc事件
      this.$emit("abc", { name: "吊毛谭磊" });
    },
  },
};
</script>

Product The case uses child to parent

parent component App.vue

<template>
  <div style="border: 1px solid #ccc; margin: 5px; padding: 5px">
    <h1>父组件</h1>
    <!-- 1. 父传。自定义属性 -->
    <!-- 添加自定义事件 -->
    <MyProduct
      v-for="(item, idx) in list"
      :idx="idx"
      :key="item.id"
      :price="item.proprice"
      :info="item.info"
      :goodname="item.proname"
      @pdd="fn"
    />
  </div>
</template>

<script>
// 导入->注册->使用
import MyProduct from "./MyProduct.vue";
export default {
  data() {
    return {
      list: [
        {
          id: 1,
          proname: "超级好吃的棒棒糖",
          proprice: 18.8,
          info: "开业大酬宾, 全场8折",
        },
        {
          id: 2,
          proname: "超级好吃的大鸡腿",
          proprice: 34.2,
          info: "好吃不腻, 快来买啊",
        },
        {
          id: 3,
          proname: "超级无敌的冰激凌",
          proprice: 14.2,
          info: "炎热的夏天, 来个冰激凌了",
        },
      ],
    };
  },
  components: { MyProduct },
  methods: {
    fn(obj) {
      console.log("父组件,收到了pdd事件", obj);
      // 计算砍了几元 相减  再进行重新赋值
      this.list[obj.idx].proprice -= obj.ran;
    },
  },
};
</script>

<style>
</style>

child component MyProduct.vue

<template>
  <div style="border: 1px solid #ccc; margin: 5px; padding: 5px">
    <h2>标题： {{ goodname }}</h2>
    <p>价格: {{ price }}元</p>
    <p>{{ info }}</p>
    <button @click="bargain">随机砍价</button>
  </div>
</template>

<script>
export default {
  // 子接收
  props: ["goodname", "price", "info", "idx"],
  methods: {
    bargain() {
      // 随机数字
      const ran = Math.ceil(Math.random() * 10);
      // 触发自定义事件
      // 为了知道具体是哪个商品要减少价格，所以要回传idx下标
      this.$emit("pdd", { idx: this.idx, ran });
    },
  },
};
</script>

<style>
</style>

Effect display

(Learning video sharing: web front-end development, Basic programming video）

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