是否可以創(chuàng)建一個(gè)可以使用多個(gè)值來確定我的字段是否有效的驗(yàn)證器？例如，如果客戶首選的聯(lián)系方式是通過電子郵件，則必須填寫電子郵件字段。謝謝。更新了示例代碼...    import {Component, View} from 'angular2/angular2';    import {FormBuilder, Validators, formDirectives, ControlGroup} from 'angular2/forms';    @Component({        selector: 'customer-basic',        viewInjector: [FormBuilder]    })    @View({        templateUrl: 'app/components/customerBasic/customerBasic.html',        directives: [formDirectives]    })    export class CustomerBasic {        customerForm: ControlGroup;        constructor(builder: FormBuilder) {            this.customerForm = builder.group({                firstname: [''],                lastname: [''],                validateZip: ['yes'],                zipcode: ['', this.zipCodeValidator]                 // I only want to validate using the function below if the validateZip control is set to 'yes'            });        }        zipCodeValidator(control) {            if (!control.value.match(/\d\d\d\d\d(-\d\d\d\d)?/)) {                return { invalidZipCode: true };            }        }    }