如何将编辑表单的值与 angular 5 中的对象数组绑定? [英] How do I bind values of edit form with array of object in angular 5?

问题描述

我有一组 Student 对象.界面如下所示:

interface 学生{标题:字符串；名字:字符串；姓氏:字符串；dob:字符串；年龄:数量；}

我要编辑title、firstName &姓氏.

表单将包含学生对象数组.从数据库中获取的对象中已经有一些数据.title 是一个下拉列表，firstName 和 lastName 是文本框.

将会有一个保存按钮，点击该按钮后，表单的值应该被捆绑并通过Student[]发送到打字稿.

我怎样才能做到这一点?

解决方案

您可以为此使用反应式表单.

首先获取您的数据并相应地生成一个FormGroup.我在 ngOnInit 方法中使用 FormBuilder 来做到这一点.

无论您从 API 获得什么，都可以映射为 FormGroup(s) 的 FormArray.

现在在模板中，您只需在选择列表上使用 formControlName 指令，即可使用 title 属性的 API 数据自动填充它.

试试这个:

import { Component } from "@angular/core";import { FormGroup, FormArray, FormBuilder, FormControl } from "@angular/forms";从@angular/common/http"导入 { HttpClient };接口学生{标题:字符串；名字:字符串；姓氏:字符串；dob:字符串；年龄:数量；}@成分({选择器:我的应用程序"，templateUrl: "./app.component.html",styleUrls: ["./app.component.css"]})导出类 AppComponent {name = "角度";表格:表格组；构造函数(私有 http:HttpClient，私有 fb:FormBuilder){}ngOnInit() {this.http.get("/assets/data.json").subscribe((students: Array) => {this.form = this.fb.group({学生:this.fb.array(student.map(student =>这个.fb.group({标题: [student.title],名字:[student.firstName]，姓氏:[学生.姓氏]，dob: [student.dob],年龄:[student.age]})))});});}提交(){console.log("表单值:", this.form.value);}}

在模板中:

<div [formGroupName]="i"><label for="title">标题</label><select name="title" id="title" formControlName="title"><option value="" disabled>选择</option><option value="Mr.">Mr.</option><option value="Mrs.">Mrs.</option><option value="Ms.">Ms.</option></选择><br><label for="firstName">名字</label><input type="text" id="firstName" formControlName="firstName"><br><label for="lastName">姓氏</label><input type="text" id="lastName" formControlName="lastName"><br><label for="dob">DOB</label><input type="text" id="dob" formControlName="dob"><br><label for="age">年龄</label><input type="text" id="age" formControlName="age"><br><小时><br>

<button type="submit">提交</button></表单>

<小时><块引用>

这是一个 工作代码示例供您参考.

I have an Array of Student Objects. The interface looks something like this:

interface Student {
  title: string;
  firstName: string;
  lastName: string;
  dob: string;
  age: number;
}

I want to edit title, firstName & lastName.

The form will have array of student objects. There is already some data in objects fetched from db. title is a dropdown, firstName and lastName are textboxes.

There will be a save button, on click of which the values of the form should be bundled and sent through Student[] to typescript.

How can I achieve this?

解决方案

You could use a Reactive Form for this.

First get your data and generate a FormGroup accordingly. I'm doing that using FormBuilder in the ngOnInit method.

Whatever you get from the API can be mapped as a FormArray of FormGroup(s).

Now in the template, you would just have to use the formControlName directive on a select list to auto-populate it with the API data for the title property.

Give this a try:

import { Component } from "@angular/core";
import { FormGroup, FormArray, FormBuilder, FormControl } from "@angular/forms";
import { HttpClient } from "@angular/common/http";

interface Student {
  title: string;
  firstName: string;
  lastName: string;
  dob: string;
  age: number;
}

@Component({
  selector: "my-app",
  templateUrl: "./app.component.html",
  styleUrls: ["./app.component.css"]
})
export class AppComponent {
  name = "Angular";
  form: FormGroup;
  constructor(private http: HttpClient, private fb: FormBuilder) {}

  ngOnInit() {
    this.http.get("/assets/data.json").subscribe((students: Array<Student>) => {
      this.form = this.fb.group({
        students: this.fb.array(
          students.map(student =>
            this.fb.group({
              title: [student.title],
              firstName: [student.firstName],
              lastName: [student.lastName],
              dob: [student.dob],
              age: [student.age]
            })
          )
        )
      });
    });
  }

  onSubmit() {
    console.log("Form Value: ", this.form.value);
  }
}

And in the template:

<form 
  *ngIf="form" 
  [formGroup]="form" 
  (submit)="onSubmit()">
  <div 
    formArrayName="students" 
    *ngFor="let studentFormGroup of form.controls['students'].controls; let i = index;">
    <div [formGroupName]="i">
      <label for="title">Title</label>
      <select name="title" id="title" formControlName="title">
        <option value="" disabled>Select</option>
        <option value="Mr.">Mr.</option>
        <option value="Mrs.">Mrs.</option>
        <option value="Ms.">Ms.</option>
      </select>
      <br>
      <label for="firstName">First Name</label>
      <input type="text" id="firstName" formControlName="firstName">
      <br>
      <label for="lastName">Last Name</label>
      <input type="text" id="lastName" formControlName="lastName">
      <br>
      <label for="dob">DOB</label>
      <input type="text" id="dob" formControlName="dob">
      <br>
      <label for="age">Age</label>
      <input type="text" id="age" formControlName="age">
      <br>
      <hr>
      <br>
    </div>
  </div>
  <button type="submit">Submit</button>
</form>

---

Here's a Working Code Sample for your ref.

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