在ElementUI中$ref是什么意思？

Question

我现在正在研究元素ui，在submitForm方法中的ref之前有一个符号$。符号不是什么意思？

<template>
  <el-form :model="ruleForm" :rules="rules" ref="ruleForm" label-width="120px" class="demo-ruleForm">
  <el-form-item label="Activity name" prop="name">
    <el-input v-model="ruleForm.name"></el-input>
  </el-form-item>
  <el-form-item label="Activity zone" prop="region">
    <el-select v-model="ruleForm.region" placeholder="Activity zone">
      <el-option label="Zone one" value="shanghai"></el-option>
      <el-option label="Zone two" value="beijing"></el-option>
    </el-select>
  </el-form-item>
  <el-form-item label="Activity time" required>
    <el-col :span="11">
      <el-form-item prop="date1">
        <el-date-picker type="date" placeholder="Pick a date" v-model="ruleForm.date1" style="width: 100%;"></el-date-picker>
      </el-form-item>
    </el-col>
    <el-col class="line" :span="2">-</el-col>
    <el-col :span="11">
      <el-form-item prop="date2">
        <el-time-picker placeholder="Pick a time" v-model="ruleForm.date2" style="width: 100%;"></el-time-picker>
      </el-form-item>
    </el-col>
  </el-form-item>
  <el-form-item label="Instant delivery" prop="delivery">
    <el-switch v-model="ruleForm.delivery"></el-switch>
  </el-form-item>
  <el-form-item label="Activity type" prop="type">
    <el-checkbox-group v-model="ruleForm.type">
      <el-checkbox label="Online activities" name="type"></el-checkbox>
      <el-checkbox label="Promotion activities" name="type"></el-checkbox>
      <el-checkbox label="Offline activities" name="type"></el-checkbox>
      <el-checkbox label="Simple brand exposure" name="type"></el-checkbox>
    </el-checkbox-group>
  </el-form-item>
  <el-form-item label="Resources" prop="resource">
    <el-radio-group v-model="ruleForm.resource">
      <el-radio label="Sponsorship"></el-radio>
      <el-radio label="Venue"></el-radio>
    </el-radio-group>
  </el-form-item>
  <el-form-item label="Activity form" prop="desc">
    <el-input type="textarea" v-model="ruleForm.desc"></el-input>
  </el-form-item>
  <el-form-item>
    <el-button type="primary" @click="submitForm('ruleForm')">Create</el-button>
    <el-button @click="resetForm('ruleForm')">Reset</el-button>
  </el-form-item>
</el-form>
</template>

<script>
  export default {
    data() {
      return {
        ruleForm: {
          name: '',
          region: '',
          date1: '',
          date2: '',
          delivery: false,
          type: [],
          resource: '',
          desc: ''
        },
        rules: {
          name: [
            { required: true, message: 'Please input Activity name', trigger: 'blur' },
            { min: 3, max: 5, message: 'Length should be 3 to 5', trigger: 'blur' }
          ],
          region: [
            { required: true, message: 'Please select Activity zone', trigger: 'change' }
          ],
          date1: [
            { type: 'date', required: true, message: 'Please pick a date', trigger: 'change' }
          ],
          date2: [
            { type: 'date', required: true, message: 'Please pick a time', trigger: 'change' }
          ],
          type: [
            { type: 'array', required: true, message: 'Please select at least one activity type', trigger: 'change' }
          ],
          resource: [
            { required: true, message: 'Please select activity resource', trigger: 'change' }
          ],
          desc: [
            { required: true, message: 'Please input activity form', trigger: 'blur' }
          ]
        }
      };
    },
    methods: {
      submitForm(formName) {
        this.$refs[formName].validate((valid) => {
          if (valid) {
            alert('submit!');
          } else {
            console.log('error submit!!');
            return false;
          }
        });
      },
      resetForm(formName) {
        this.$refs[formName].resetFields();
      }
    }
  }
</script>

Answer 1

这没什么特别的，只是添加了一个标记到键上，这样就可以清楚地知道它属于elementUI，并有助于确保它不会与您定义的键冲突。$refs对象包含Vue组件。

Answer 2

最好看看$refs的Vue.js documentation。看起来每个具有ref属性的DOM元素都会被查看。下面是ref的值，然后您可以对其调用函数(方法)。