Vue学习案例：父子通信-结合双向绑定案例

<!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>
    <div id="app">
      <cpn
        :cnum1="num1"
        :cnum2="num2"
        @num1change="num1change"
        @num2change="num2change"
      ></cpn>
    </div>

    <!-- 子模板 -->
    <template id="cpn">
      <div>
        <h2>porps:{{cnum1}}</h2>
        <h2>data:{{dnum1}}</h2>
        <!-- <input type="text" v-model="dnum1" /> -->
        <!-- v-model原理 -->
        <input type="text" :value="dnum1" @input="num1Input" />
        <h2>porps:{{cnum2}}</h2>
        <h2>data:{{dnum2}}</h2>
        <!-- v-model原理 -->
        <!-- <input type="text" v-model="dnum2" /> -->
        <input type="text" :value="dnum2" @input="num2Input" />
      </div>
    </template>
    <script src="../vue.js"></script>
    <script>
      const app = new Vue({
        el: "#app",
        data: {
          num1: 1,
          num2: 0,
        },
        methods: {
          num1change(value) {
            this.num1 = parseInt(value);
          },
          num2change(value) {
            this.num2 = parseInt(value);
          },
        },
        // 子组件
        components: {
          cpn: {
            template: "#cpn",
            props: {
              cnum1: Number,
              cnum2: Number,
            },
            data() {
              return {
                dnum1: this.cnum1,
                dnum2: this.cnum2,
              };
            },
            methods: {
              num1Input(event) {
                // 将input中的value赋值到dnum1中
                this.dnum1 = event.target.value;
                // 为了让父组件可以修改值，发出一个事件
                this.$emit("num1change", this.dnum1);

                //同时修饰dnum2的值,然后把dnum2的值再次发送出去
                this.dnum2 = this.dnum1 * 100;
                this.$emit("num2change", this.dnum2);
              },
              num2Input(event) {
                this.dnum2 = event.target.value;
                this.$emit("num2change", this.dnum2);

                this.dnum1 = this.dnum2 / 100;
                this.$emit("num1change", this.dnum1);
              },
            },
          },
        },
      });
    </script>
  </body>
</html>