element 表单验证通过必要条件控制存在与否

方案1：
const rules=[ send_server: [{ required: true, message: '必填', validator: this.a}],

 private a(rule: any, value:any, callback: Function) {
    callback(this.formData.code_is_bind === '1' && this.formData.send_server === '1' && !value ? '' : undefined)
  }
方案2：
<el-form-item
        label="多语言关联"
        :prop="'weaponAttackList.'+index+'.langMark2'"
        :rules="rules.weaponAttackList.langMark2"
        >
</el-form-item>