我只是用TypeScript和Angular2弄湿我的脚。我正在使用具有嵌套对象结构的API。我希望我的模型能够从API中镜像资源。该模型/资源,“查询”,如打字稿定义:Angular2 FormBuilder和嵌套的对象属性返回undefined
// inquiry.ts
export class Inquiry {
name: {
first: string,
last: string
};
email: string;
phone: string;
question: string;
}
我的表单组件是这样的:
import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { InquireService } from './inquire.service';
import { Inquiry } from './inquiry';
@Component({
selector: 'inquire-form',
templateUrl: './inquire-form.component.html'
})
export class InquireFormComponent implements OnInit {
inquiryForm: FormGroup;
inquiry = new Inquiry;
constructor(
private formBuilder: FormBuilder,
private inquireService: InquireService) {}
ngOnInit(): void {
this.buildForm();
}
buildForm(): void {
this.inquiryForm = this.formBuilder.group({
'firstName': [
this.inquiry.name.first, [
Validators.required,
Validators.minLength(2),
Validators.maxLength(50)
]
], ...
}
}
我得到时,我打我的路线错误是:
Error: Uncaught (in promise): TypeError: Cannot read property 'first' of undefined
当我登录this.inquiry.name
确实undefined
,但我不明白为什么。我究竟做错了什么?
你只是说明了'name'属性的类型签名是什么,但实际上并没有初始化zed它。 –
嗯。当我创建新的查询实例(在构造函数之上)时,它没有初始化吗? – Brandon
据我所知,你只是宣称一个Inquiry对象包含4个属性,一个名字为'{first:string,last:string}'和'email','phone'和'question'字符串类型。没有一个属性被明确地初始化,所以它们只有它们的默认值('undefined')。 –