Vue父子组件传值

父组件向子组件传递值：

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <!-- 父组件向子组件传地值 -->
  <div id="app">
    <!-- 子组件传递值，可以使用静态值，也可以使用动态值 -->
    <son :num="count"></son>
    <button @click="count++">加</button>
    <button @click="count--">减</button>
  </div>

  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>

  <script>
    // 子组件
    Vue.component('son', {
      template: `
        <div>
          <div>父组件传递过来的值：num:{{num}} </div>
        </div>
      `,
      // 使用props接收父组件传递的值，接收的num值子组件无法修改，只能父组件自己修改
      props: ['num']
    });

    let app = new Vue({
      el: "#app",
      data: {
        count: 0
      }
    });
  </script>

</body>

</html>

子组件向父组件传值：

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <!-- 子组件向父组件传递值 -->
  <div id="app">
    <div>子组件传递过来的值：{{count}} </div>
    <son @add-one="fadd" @incr-one="fincr"></son>
  </div>
  <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  <script>
    // 子组件
    Vue.component('son', {
      template: `
        <div>
          <div>子组件的值：{{num}}</div>
          <button @click='add'>加</button>
          <button @click='incr'>减</button>
        </div>
      `,
      data() {
        return {
          num: 0
        }
      },
      methods: {
        add() {
          this.num++
          // 调用父组件的方法，并传递参数
          this.$emit('add-one', this.num)
        },
        incr() {
          this.num--
          // 调用父组件的方法，并传递参数
          this.$emit('incr-one', this.num)
        }
      }
    });

    let app = new Vue({
      el: "#app",
      data: {
        count: 0
      },
      methods: {
        fadd(num) {
          this.count = num;
        },
        fincr(num) {
          this.count = num;
        }
      }
    });
  </script>

</body>

</html>