如何将选中的值放入

如何将选中的值放入

本文介绍了如何将选中的值放入 Angular 模板驱动表单 (ngModel) 的数组中的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我正在尝试使用模板驱动的表单,将 html 中的模型绑定到一个新实例,比如 Person.我未能成功地为复选框创建正确绑定到模型上的单个数组属性.

这个想法是数据将来自 api 或其他来源,通过 *ngFor 动态呈现复选框并将所选内容绑定到 Person 模型属性,这将是一个数字数组.例如:

class Person {名字:字符串;someCheckboxPropList: number[];}

数据可以是任何东西

const dynamicData = [{名称:'名称1',值:1},{名称:'name2',值:2}];

我的预期输出将类似于 [ 1, 2 ] 的内容,如果两个值都被检查,并且如果只检查第二个值 [ 2 ].

以下是 PersonComponent.ts 文件的示例

@Component({ ... })导出类 PersonComponent {提交=假;模型 = 新人();构造函数(){}提交(表单){this.submitted = true;控制台日志(表单);}}

我现在的组件 html 文件.

<input type="text" [(ngModel)] name="person.firstName"><div *ngFor="let dataItem of dynamicData" ><label>{{dataItem.name}}</label>

</表单>

这不起作用(无论如何都是示例代码).

解决方案

这个想法是有两个东西:Person 和 PersonForm,所以,例如

person={firstName:"Jessy",props:[1,2]//但personForm={firstName:"Jessy",props:[true,true]

所以,创建两个函数

 createForm(person) {返回 {名字:person.firstName,道具:this.dynamicData.map(x => person.props.indexOf(x.value) >= 0)}}检索数据(personForm){让道具:数字[] = [];personForm.props.forEach((v, index) => {如果(五)props.push(this.dynamicData[index].value)})返回 {名字:personForm.firstName,道具:道具}}

好吧,我们已经拥有了我们需要的一切.当我们收到一个人时,创建一个 personForm ,它是我们在表单中更改的数据.在提交中只需调用retrieveData 来获取person 的值.

当我们让一个人创建一个personForm时,例如

this.service.getPerson().subscribe(person=>{this.personForm=createForm(person)})

我们的表格

<input name="firtName" [(ngModel)]="personForm.firstName"><div *ngFor="let dynamicData 项;let i=index"><input name="{{'prop'+i}}"type="checkBox" [(ngModel)]="personForm.props[i]">{{item.name}}

</表单>{{personForm|json}}<br/>{{retrieveData(personForm)|json}}

还有我们的 sendData 函数

sendData(personForm){console.log(this.retrieveData(personForm))}

我做了一个简单的stackblitz

更新

注意:我们可以使用 spred 操作符来定义属性,所以

 createForm(person) {返回 {...person,//person的所有属性,但是道具:this.dynamicData.map(x => person.props.indexOf(x.value) >= 0)}}检索数据(personForm){让道具:数字[] = [];personForm.props.forEach((v, index) => {如果(五)props.push(this.dynamicData[index].value)})返回 {..personForm,//personForm的所有属性,但是道具:道具}}

注意2:在现实世界"中,人员来自服务.考虑服务获取/接收personForm"并将要转换的功能放在服务中的想法

//服务中获取人(){返回 this.httpClient.get("...").map(res=>this.createForm(res))}savePerson(personForm){return this.httpClient.post("...",this.retrieveData(personForm))}

I'm attempting to use template driven forms, binding to a model in the html to a new instance of lets say Person. I've been unsuccessful in creating a proper binding for checkboxes to a single array property on my model.

The idea is data will come from an api or other source, dynamically render checkboxes via *ngFor and bind what is selected to the Person models property which would be an array of numbers. For example:

class Person {
  firstName: string;
  someCheckboxPropList: number[];
}

and data could be anything really

const dynamicData = [
  { name: 'name1', value: 1 },
  { name: 'name2', value: 2 }
];

my expected output would be something along the lines of [ 1, 2 ] if both values where to be checked and if only the second was checked [ 2 ].

Here's a sample of what the PersonComponent.ts file might look like

@Component({ ... })
export class PersonComponent {

    submitted = false;

    model = new Person();

    constructor() { }

    onSubmit(form) {
        this.submitted = true;
        console.log(form);
    }

}

And where I'm at with the components html file.

<form (ngSubmit)="onSubmit(form)" #form="ngForm">

    <input type="text" [(ngModel)] name="person.firstName">

    <div *ngFor="let dataItem of dynamicData" >
        <input
            type="checkbox"
            ngModel
            name="dynamicData"
            [value]="dataItem.value">
        <label>{{dataItem.name}}</label>
    </div>

</form>

This does not work (and is sample code anyway).

解决方案

the idea is have two things: Person and PersonForm, so,e.g

person={firstName:"Jessy",props:[1,2]
//but
personForm={firstName:"Jessy",props:[true,true]

So, make two functions

  createForm(person) {
    return {
      firstName: person.firstName,
      props: this.dynamicData.map(x => person.props.indexOf(x.value) >= 0)
    }
  }
  retrieveData(personForm) {
    let props: number[] = [];
    personForm.props.forEach((v, index) => {
      if (v)
        props.push(this.dynamicData[index].value)
    }
    )
    return {
      firstName: personForm.firstName,
      props: props
    }
  }

Well, we have already all we need. When we received a person, create a personForm that it's the data we change in the form. In submit simply call to retrieveData to get the value of person.

When we have a person create a personForm,e.g.

this.service.getPerson().subscribe(person=>
    {
       this.personForm=createForm(person)
    }
)

Our form

<form *ngIf="personForm" (submit)="sendData(personForm)">
  <input name="firtName" [(ngModel)]="personForm.firstName">
  <div *ngFor="let item of dynamicData;let i=index">
  <input name="{{'prop'+i}}"
         type="checkBox" [(ngModel)]="personForm.props[i]">{{item.name}}
  </div>
  <button>Submit</button>
</form>
{{personForm|json}}<br/>
{{retrieveData(personForm)|json}}

And our sendData function

sendData(personForm)
{
    console.log(this.retrieveData(personForm))
}

I make a simple stackblitz

Update

NOTE:We can use the spred operator to asing properties, so

  createForm(person) {
    return {
      ...person, //All the properties of person, but
      props: this.dynamicData.map(x => person.props.indexOf(x.value) >= 0)
    }
  }
  retrieveData(personForm) {
    let props: number[] = [];
    personForm.props.forEach((v, index) => {
      if (v)
        props.push(this.dynamicData[index].value)
    }
    )
    return {
      ..personForm, //all the properties of personForm, but
      props: props
    }
  }

NOTE2: In a "real world" the persons goes from a service. Consider the idea that service get/received the "personForm" and put the functions to transform in the service

//in service
getPerson()
{
    return this.httpClient.get("...").map(res=>this.createForm(res))
}
savePerson(personForm)
{
    return this.httpClient.post("...",this.retrieveData(personForm))
}

这篇关于如何将选中的值放入 Angular 模板驱动表单 (ngModel) 的数组中的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

09-02 02:21