element-ui设置下拉选择切换必填和非必填

<template>
  <div>
    <el-form
      :model="ruleForm"
      :rules="rules"
      ref="ruleForm"
      label-width="100px"
      class="demo-ruleForm"
    >
      <el-form-item label="活动名称" prop="name" :required="isHaveTo">
        <el-input v-model="ruleForm.name"></el-input>
      </el-form-item>
      <el-form-item label="活动区域" prop="region">
        <el-select v-model="ruleForm.region" placeholder="请选择活动区域" style="width:100%">
          <el-option label="必填" value="0"></el-option>
          <el-option label="非必填" value="1"></el-option>
        </el-select>
      </el-form-item>
      <el-form-item>
        <el-button type="primary" @click="submitForm('ruleForm')">立即创建</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
 
<script>
export default {
  name: "HelloWorld",
  data() {
    // 验证活动名称的函数
    let validateName = (rule, value, callback) => {
      // 当活动名称为空值且为必填时，抛出错误，反之通过校验
      if (this.ruleForm.name === "" && this.isHaveTo) {
        callback(new Error("请输入活动名称"));
      } else {
        callback();
      }
    };
    return {
      ruleForm: {
        name: "",
        region: ""
      },
      rules: {
        name: [{ validator: validateName }],
        region: [
          { required: true, message: "请选择类型", trigger: "blur" }
        ]
      }
    };
  },
  computed: {
    isHaveTo: function() {
      return this.ruleForm.region !== `1`;
    }
  },
  methods: {
    submitForm(formName) {
      this.$refs[formName].validate(valid => {
        if (valid) {
          console.log(`已提交表单`);
        } else {
          console.log("error submit!!");
          return false;
        }
      });
    }
  }
};
</script>