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更新作为 Angular2 中 formArray 中的文件输入的 formControl
[英] Update a formControl that is a file input in a formArray in Angular2
本文介绍了更新作为 Angular2 中 formArray 中的文件输入的 formControl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
我有以下代码:
import { Component, OnInit, ElementRef } from '@angular/core';从@angular/forms"导入 { FormArray、FormBuilder、FormControl、FormGroup、Validators}@零件({选择器:'app-root'，templateUrl: './app.component.html',styleUrls: ['./app.component.css']})导出类 AppComponent 实现 OnInit {显示排序:布尔值 = 假；表格:表格组；名称:表单控件；sortSelf:表单控件；sortItem:FormArray；locationItems:FormArray；构造函数(私有_fb:FormBuilder，私有_elementRef:ElementRef){}ngOnInit(): 无效 {this.sortItem = this._fb.array([this.initSort()]);this.form = this._fb.group({sortItem: this.sortItem});}initSort() {返回 this._fb.group({locationPicture: new FormControl('', []),locationItems: this._fb.array([this.initSortItems()])})}initSortItems() {返回 this._fb.group({itemPicture: new FormControl('', [])})}添加排序(){this.sortItem.push(this.initSort());}addSortLocationItem(i?: number, t?: number) {const 控件:FormArray = this.sortItem.at(i).get('locationItems');control.push(this.initSortItems());}showImage(event, level?: string, i?: number, t?: number){让文件 = event.target.files[0];if(level === 'locationPicture'){(<FormArray>this.sortItem.at(i)).controls['locationPicture'].setValue(file, {onlySelf: true});}别的{(<FormArray>this.sortItem.at(i).get('locationItems')).at(t).get('itemPicture').setValue(file, {onlySelf: true});}}下一个(值，有效:布尔值){console.log(`这是值 ${JSON.stringify(value, null, 4)}`);}}
标记:
<form class="" action="index.html" method="post" [formGroup]="form" (ngSubmit)="next(form.value, form.valid)"><div class="form-group"><div formArrayName="sortItem" class=""><div class="top-buffer-small"><a (click)="addSort()" style="cursor: default">添加排序位置 +</a>
<div *ngFor="let sortLocation of sortItem.controls; let i=index"><div [formGroupName]="i" class=""><div class="form-group"><label>位置图片</label><input type="file" formControlName="locationPicture" class="form-control locationPicture" accept="image/*" capture="camera" (change)="showImage($event, 'locationPicture', i, t)"><!-- <input type="file" formControlName="locationPicture" (change)="showImage($event)"/>--><img src="" alt="" class="location-image" width="80" height="80"><small class="form-text text-muted" [hidden]="sortItem.controls[i].controls.locationPicture.valid">图片为必填项</小>
<div formArrayName="locationItems" class="col-md-10 col-md-offset-1"><div class="row"><a (click)="addSortLocationItem(i,t)" style="cursor: default">添加项目 +</a>
<!-- <div class="from-group" *ngFor="let eachItem of form.controls.sortItem.controls[i].controls.locationItems.controls; let t=index">--><div class="form-group" *ngFor="let eachItem of sortLocation.get('locationItems').controls; let t=index"><div [formGroupName]="t"><div class="form-group"><label>项目图片</label><input type="file" formControlName="itemPicture" class="form-control itemPicture" capture="camera" (change)="showImage($event, 'itemPicture', i, t)"><img src="" alt="" class="item-image" width="80" height="80"><small class="form-text text-muted" [hidden]="sortItem.controls[i].controls.locationItems.controls[t].controls.itemPicture.valid">图片为必填项</小>
<div class="clearfix"></div>
<div class="text-center"><button type="submit" name="button" class="btn btn-primary" [disabled]="form.invalid">提交</button>
</表单>
我试图通过更新表单控件值来更新 showImage 方法中的表单.但是，我无法使用图片更新表单.当我尝试将其上传到locationPicture"和itemPicture"时，出现以下错误:
未能在HTMLInputElement"上设置value"属性:此输入元素接受一个文件名，该文件名只能以编程方式设置为空字符串.
请对此提供任何帮助
解决方案
我也遇到了这个问题，不过我们可以分别处理file和其他表单域.
这是我的代码，我想将 FormData Object 发布到 Django REST API，这个 formData 包含字符串和图像，还有 user_name 和 password.我创建了一个组件 - upload-image-form
这是我要贴的，一个Image类(我自己定义的)
//images.ts导出类图像{构造函数(公共 ID:号码，public created: string,//由后端设置公共用户 ID:号码，公共文件网址:字符串，公共所有者:字符串，公共des?:字符串，公共本地图像?:文件，) { }}
这是我的组件
//upload-image-form.component.ts从'@angular/core'导入{组件，OnInit，输入}；从'@angular/forms/forms' 导入 { NgForm };从'@angular/forms' 导入 { FormControl, FormGroup, FormBuilder };从'../image'导入{图像}；从'../user'导入{用户}；从 '../image.service' 导入 { ImageService };@零件({选择器:'app-upload-image-form',templateUrl: './upload-image-form.component.html',styleUrls: ['./upload-image-form.component.css']})导出类 UploadImageFormComponent 实现 OnInit {@Input() 用户:用户；//该值来自父组件用户详细信息的模板私人文件:文件；私有表单数据:FormData = new FormData();私有图像形式:FormGroup；私人提交=假；private imageUrl = 'http://192.168.201.211:8024/images/';私人密码:字符串；构造函数(私有图像服务:图像服务，私人 fb:FormBuilder，) { }ngOnInit() {控制台日志(this.user)；this.createFrom(this.user);//在这里创建表单，这样我们就可以得到 this.user 的值}创建从(用户:用户){//我没有在这个表单中放置文件字段this.imageForm = this.fb.group({编号:1，创建:'20170825'，用户 ID:用户 ID，fileUrl: 'http://images.fineartamerica.com/images-medium-large-5/mt-shuksan-picture-lake-dennis-romano.jpg',所有者:user.username，des: '',密码:'',})控制台日志(用户)；}//https://stackoverflow.com/a/41465502/2803344//从表单输入中获取文件对象onChange(事件:EventTarget){让 eventObj: MSInputMethodContext = <MSInputMethodContext>事件;让目标:HTMLInputElement = eventObj.target;让文件:FileList = target.files;this.file = 文件 [0];}提交(){//分别处理字符串字段和文件this.submitted = true;控制台.log(this.file);//文件在这里，被 onChange() 捕获控制台日志(this.imageForm.value)；//其他字段在这里，被formGroup捕获this.formData.append('localImage', this.file, this.file.name);for (let item in this.imageForm.value) {控制台日志(项目)如果(项目！== '密码'){this.formData.append(item, this.imageForm.value[item]);}别的 {this.password = this.imageForm.value[item];}}//console.log('###这里是整个表单数据');控制台日志(this.formData)；console.log(this.formData.get('fileUrl'));console.log(this.user.username);this.imageService.post(this.formData, this.user.username, this.password).then(res =>{控制台日志(res)；});}onClick(形式:FormGroup){表单.重置({用户 ID:this.user.id，所有者:this.user.username,创建:'20170825'，fileUrl: 'http://www.fujifilm.com.sg/Products/digital_cameras/x/fujifilm_x_t1/sample_images/img/index/ff_x_t1_001.JPG',})this.submitted=false;控制台日志(表单值)；}}
这是我的模板
<div [隐藏]="已提交" *ngIf="用户"><h2>上传新图片</h2><form [formGroup]="imageForm" (ngSubmit)="onSubmit()" ><div class="form-group"><label for="fileUrl">文件网址</label><input type="url" class="form-control" id="fileUrl"formControlName="fileUrl" required><div [hidden]="imageForm.get('fileUrl').valid || imageForm.get('fileUrl').pristine"class="警报警报-危险">文件网址为必填项<p>{{imageForm.get('fileUrl').valid |json}}</p><p>{{imageForm.get('fileUrl').value |json}}</p>
<!-- 上传图片不要在 formGroup 中定义这个字段--><div class="form-group"><label for="localImage">本地文件</label><input type="file" class="form-control" id="localImage"(change)="onChange($event)" accept=".jpg, .png" >
<div class="form-group"><label for="des">描述</label><input type="text" class="form-control" id="des"formControlName="des">
<div class="form-group"><label for="userId">用户 ID</label><input type="text" class="form-control" id="userId"formControlName="userId" 只读><p>{{imageForm.get('userId').value |json}}</p>
<div class="form-group"><label for="owner">所有者</label><input type="text" class="form-control" id="owner"formControlName="owner" readonly>
<!-- 输入用户密码--><div class="form-group"><label for="pw">密码</label><input type="password" class="form-control" id="pw"formControlName="pw" required>
<button type="submit" class="btn btn-success" [disabled]="!imageForm.valid">提交</button></表单>
最后，这是我的图像服务
//image.service.ts从@angular/core"导入{可注射}；从@angular/http"导入{标题，Http，RequestOptions}；导入 'rxjs/add/operator/toPromise';从./image"导入{图像}；从'./user'导入{用户}；@Injectable()导出类 ImageService {private imageUrl = 'http://192.168.201.211:8024/images/';//设置授权头，https://stackoverflow.com/a/34465070/2803344createAuthorizationHeader(标题:标题，名称:字符串，密码:字符串){headers.append('授权', '基本' +btoa(`${name}:${pw}`));}创建选项(名称:字符串，密码:字符串){让标题=新标题()；this.createAuthorizationHeader(headers, name, pw);//headers.append('Content-Type', 'application/json');//没有这个//headers.append('Content-Type', 'multipart/form-data');//没有这个let options = new RequestOptions({ headers: headers });退货选项；}构造函数(私有http:Http){}getImageById(id: number): Promise{const url = `${this.imageUrl}`;控制台日志(网址)；让标题=新标题()；让令牌 = '令牌';headers.append('X-Auth-Token', token);返回 this.http.get(url, {headers: headers}).承诺()//.then(res => res.json().data as Image).then(res => console.log(res)).catch(this.handleError);}getImageByUrl(url: string): Promise{返回 this.http.get(url).承诺().then(res => res.json() as Image)//.then(res => console.log(res)).catch(this.handleError);}post(formData: FormData, user: string, pw: string): Promise{让选项 = this.createOptions(user, pw);console.log('我们会有一个帖子！');console.log(formData.get('localImage'));console.log(formData.get('fileUrl'));console.log(formData.get('des'));返回 this.http.post(this.imageUrl, formData, options).承诺().then(res => res.json() as Image).catch(this.handleError);}private handleError(error: any): Promise{console.error('发生错误', error);//仅用于演示目的返回 Promise.reject(error.message || error);}}
你可以在github中找到整个项目，https://github.com/OnlyBelter/图像共享系统2.
I have the code below:
import { Component, OnInit, ElementRef } from '@angular/core';
import { FormArray, FormBuilder, FormControl, FormGroup, Validators } from '@angular/forms'
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {
showSort: boolean = false;
form: FormGroup;
name: FormControl;
sortSelf: FormControl;
sortItem: FormArray;
locationItems: FormArray;
constructor(private _fb: FormBuilder, private _elementRef: ElementRef ) {
}
ngOnInit(): void {
this.sortItem = this._fb.array([this.initSort()]);
this.form = this._fb.group({
sortItem: this.sortItem
});
}
initSort() {
return this._fb.group({
locationPicture: new FormControl('', []),
locationItems: this._fb.array([
this.initSortItems()
])
})
}
initSortItems() {
return this._fb.group({
itemPicture: new FormControl('', [])
})
}
addSort() {
this.sortItem.push(this.initSort());
}
addSortLocationItem(i?: number, t?: number) {
const control: FormArray = <FormArray> this.sortItem.at(i).get('locationItems');
control.push(this.initSortItems());
}
showImage(event, level?: string, i?: number, t?: number){
let file = event.target.files[0];
if(level === 'locationPicture'){
(<FormArray>this.sortItem.at(i)).controls['locationPicture'].setValue(file, {onlySelf: true});
}else{
(<FormArray>this.sortItem.at(i).get('locationItems')).at(t).get('itemPicture').setValue(file, {onlySelf: true});
}
}
next(value, valid: boolean){
console.log(`this is value ${JSON.stringify(value, null, 4)}`);
}
}
Mark Up:
<div class="col-md-8 col-md-offset-2">
<form class="" action="index.html" method="post" [formGroup]="form" (ngSubmit)="next(form.value, form.valid)">
<div class="form-group">
<div formArrayName="sortItem" class="">
<div class="top-buffer-small">
<a (click)="addSort()" style="cursor: default">
Add Sort Location +
</a>
</div>
<div *ngFor="let sortLocation of sortItem.controls; let i=index">
<div [formGroupName]="i" class="">
<div class="form-group">
<label>Location Picture</label>
<input type="file" formControlName="locationPicture" class="form-control locationPicture" accept="image/*" capture="camera" (change)="showImage($event, 'locationPicture', i, t)">
<!-- <input type="file" formControlName="locationPicture" (change)="showImage($event)" /> -->
<img src="" alt="" class="location-image" width="80" height="80">
<small class="form-text text-muted" [hidden]="sortItem.controls[i].controls.locationPicture.valid">
Picture is required
</small>
</div>
<div formArrayName="locationItems" class="col-md-10 col-md-offset-1">
<div class="row">
<a (click)="addSortLocationItem(i,t)" style="cursor: default">
Add Item +
</a>
</div>
<!-- <div class="from-group" *ngFor="let eachItem of form.controls.sortItem.controls[i].controls.locationItems.controls; let t=index"> -->
<div class="form-group" *ngFor="let eachItem of sortLocation.get('locationItems').controls; let t=index">
<div [formGroupName]="t">
<div class="form-group">
<label>Item Picture</label>
<input type="file" formControlName="itemPicture" class="form-control itemPicture" capture="camera" (change)="showImage($event, 'itemPicture', i, t)">
<img src="" alt="" class="item-image" width="80" height="80">
<small class="form-text text-muted" [hidden]="sortItem.controls[i].controls.locationItems.controls[t].controls.itemPicture.valid">
Picture is required
</small>
</div>
</div>
</div>
</div>
<div class="clearfix"></div>
</div>
</div>
</div>
</div>
<div class="text-center">
<button type="submit" name="button" class="btn btn-primary" [disabled]="form.invalid">Submit</button>
</div>
</form>
</div>
I am trying to update the form within the showImage method by updating the formcontrol values. However, I cannot get the form to update with the picture. When I try to upload it on the 'locationPicture' and 'itemPicture', I get the following error:
Failed to set the 'value' property on 'HTMLInputElement': This input element accepts a filename, which may only be programmatically set to the empty string.
Please any help with this will be great
解决方案
I also got this problem, but we can deal with file and other form field separately.
This is my code, I want to post a FormData Object to Django REST API, this formData contains both strings and image, also with user_name and password. I created a component - upload-image-form
This is what I want to post, an Image class(I define it by myself)
// images.ts
export class Image {
constructor(
public id: number,
public created: string, // set by back end
public userId: number,
public fileUrl: string,
public owner: string,
public des?: string,
public localImage?: File,
) { }
}
This is my component
// upload-image-form.component.ts
import { Component, OnInit, Input } from '@angular/core';
import { NgForm } from '@angular/forms/forms';
import { FormControl, FormGroup, FormBuilder } from '@angular/forms';
import { Image } from '../image';
import { User } from '../user';
import { ImageService } from '../image.service';
@Component({
selector: 'app-upload-image-form',
templateUrl: './upload-image-form.component.html',
styleUrls: ['./upload-image-form.component.css']
})
export class UploadImageFormComponent implements OnInit {
@Input() user: User; // this value comes from parent component user-detail's tempolate
private file: File;
private formData: FormData = new FormData();
private imageForm: FormGroup;
private submitted = false;
private imageUrl = 'http://192.168.201.211:8024/images/';
private password: string;
constructor(
private imageService: ImageService,
private fb: FormBuilder,
) { }
ngOnInit() {
console.log(this.user);
this.createFrom(this.user); // create form here, so we can get this.user's value
}
createFrom(user: User) {
// I didn't put file field in this form
this.imageForm = this.fb.group({
id: 1,
created: '20170825',
userId: user.id,
fileUrl: 'http://images.fineartamerica.com/images-medium-large-5/mt-shuksan-picture-lake-dennis-romano.jpg',
owner: user.username,
des: '',
pw: '',
})
console.log(user);
}
// https://stackoverflow.com/a/41465502/2803344
// get a file object from form input
onChange(event: EventTarget) {
let eventObj: MSInputMethodContext = <MSInputMethodContext> event;
let target: HTMLInputElement = <HTMLInputElement> eventObj.target;
let files: FileList = target.files;
this.file = files[0];
}
onSubmit() {
// deal with string fields and file separately
this.submitted = true;
console.log(this.file); // file is here, captured by onChange()
console.log(this.imageForm.value); // other fields are here, captured by formGroup
this.formData.append('localImage', this.file, this.file.name);
for (let item in this.imageForm.value) {
console.log(item)
if (item !== 'pw') {
this.formData.append(item, this.imageForm.value[item]);
}
else {
this.password = this.imageForm.value[item];
}
}
// console.log('###here is the total form data');
console.log(this.formData);
console.log(this.formData.get('fileUrl'));
console.log(this.user.username);
this.imageService.post(this.formData, this.user.username, this.password)
.then(res =>{
console.log(res);
});
}
onClick(form: FormGroup) {
form.reset({
userId: this.user.id,
owner: this.user.username,
created: '20170825',
fileUrl: 'http://www.fujifilm.com.sg/Products/digital_cameras/x/fujifilm_x_t1/sample_images/img/index/ff_x_t1_001.JPG',
})
this.submitted=false;
console.log(form.value);
}
}
This is my template
<!-- upload-image-form.component.html -->
<div [hidden]="submitted" *ngIf="user">
<h2>Upload New Image</h2>
<form [formGroup]="imageForm" (ngSubmit)="onSubmit()" >
<div class="form-group">
<label for="fileUrl">File Url</label>
<input type="url" class="form-control" id="fileUrl"
formControlName="fileUrl" required>
<div [hidden]="imageForm.get('fileUrl').valid || imageForm.get('fileUrl').pristine"
class="alert alert-danger">
File Url is required
</div>
<p>{{imageForm.get('fileUrl').valid | json}}</p>
<p>{{imageForm.get('fileUrl').value | json}}</p>
</div>
<!-- upload an image
don't define this field in formGroup-->
<div class="form-group">
<label for="localImage">Local File</label>
<input type="file" class="form-control" id="localImage"
(change)="onChange($event)" accept=".jpg, .png" >
</div>
<div class="form-group">
<label for="des">Description</label>
<input type="text" class="form-control" id="des"
formControlName="des">
</div>
<div class="form-group">
<label for="userId">User ID</label>
<input type="text" class="form-control" id="userId"
formControlName="userId" readonly>
<p>{{imageForm.get('userId').value | json}}</p>
</div>
<div class="form-group">
<label for="owner">Owner</label>
<input type="text" class="form-control" id="owner"
formControlName="owner" readonly>
</div>
<!-- input user's password -->
<div class="form-group">
<label for="pw">password</label>
<input type="password" class="form-control" id="pw"
formControlName="pw" required>
</div>
<button type="submit" class="btn btn-success" [disabled]="!imageForm.valid">Submit</button>
</form>
</div>
At last, this is my image service
// image.service.ts
import { Injectable } from '@angular/core';
import { Headers, Http, RequestOptions } from "@angular/http";
import 'rxjs/add/operator/toPromise';
import { Image } from "./image";
import { User } from './user';
@Injectable()
export class ImageService {
private imageUrl = 'http://192.168.201.211:8024/images/';
//set headers for authorization, https://stackoverflow.com/a/34465070/2803344
createAuthorizationHeader(headers: Headers, name: string, pw: string) {
headers.append('Authorization', 'Basic ' +
btoa(`${name}:${pw}`));
}
createOptions(name: string, pw: string) {
let headers = new Headers();
this.createAuthorizationHeader(headers, name, pw);
// headers.append('Content-Type', 'application/json'); // without this
// headers.append('Content-Type', 'multipart/form-data'); // without this
let options = new RequestOptions({ headers: headers });
return options;
}
constructor(private http: Http) { }
getImageById(id: number): Promise<Image> {
const url = `${this.imageUrl}`;
console.log(url);
let headers = new Headers();
let token = 'token';
headers.append('X-Auth-Token', token);
return this.http.get(url, {headers: headers})
.toPromise()
// .then(res => res.json().data as Image)
.then(res => console.log(res))
.catch(this.handleError);
}
getImageByUrl(url: string): Promise<Image> {
return this.http.get(url)
.toPromise()
.then(res => res.json() as Image)
// .then(res => console.log(res))
.catch(this.handleError);
}
post(formData: FormData, user: string, pw: string): Promise<Image> {
let options = this.createOptions(user, pw);
console.log('we will have a post!');
console.log(formData.get('localImage'));
console.log(formData.get('fileUrl'));
console.log(formData.get('des'));
return this.http.post(this.imageUrl, formData, options)
.toPromise()
.then(res => res.json() as Image)
.catch(this.handleError);
}
private handleError(error: any): Promise<any> {
console.error('An error occurred', error); // for demo purposes only
return Promise.reject(error.message || error);
}
}
You can find the whole project in github, https://github.com/OnlyBelter/image-sharing-system2.
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