我是Angular的初学者，我想知道如何创建Angular 5文件上传部分，我试图找到任何教程或文档，但我在任何地方都看不到任何东西。对此有什么想法吗?我尝试了ng4-files，但它不适用于Angular 5
当前回答
好的，因为这个线程出现在谷歌的第一个结果中，对于其他有同样问题的用户，你不需要像trueboroda指出的那样重新开始，有ng2-file-upload库，它简化了使用angular 6和7上传文件的过程，你所需要做的是:
安装最新的Angular CLI
yarn add global @angular/cli
出于兼容性考虑，请安装rx-compat
npm install rxjs-compat --save
安装ng2-file-upload
npm install ng2-file-upload --save
在你的模块中导入FileSelectDirective指令。
import { FileSelectDirective } from 'ng2-file-upload';
Add it to [declarations] under @NgModule:
declarations: [ ... FileSelectDirective , ... ]
在你的组件中
import { FileUploader } from 'ng2-file-upload/ng2-file-upload';
...
export class AppComponent implements OnInit {
public uploader: FileUploader = new FileUploader({url: URL, itemAlias: 'photo'});
}
模板
<input type="file" name="photo" ng2FileSelect [uploader]="uploader" />
为了更好地理解，你可以查看这个链接: 如何使用Angular 6/7上传文件
其他回答
在我的情况下，我使用http拦截器，事情是，默认情况下，我的http拦截器设置内容类型头为应用程序/json，但对于文件上传，我使用multer库。 稍微改变一下我的http。interceptor定义，如果请求体是FormData，它会删除头，不触及访问令牌。 下面是一部分代码，它让我很开心。
if (request.body instanceof FormData) {
request = request.clone({ headers: request.headers.delete('Content-Type', 'application/json') });
}
if (request.body instanceof FormData) {
request = request.clone({ headers: request.headers.delete('Accept', 'application/json')});
}
create-profile.html
<body>
<h1 class="font-weight-bold" >Create Advertistment</h1>
<hr />
<form [formGroup]="form" (submit)="onSubmit()">
<div>
<label class="font-weight-bold">Insert Subject name</label>
<br>
<input formControlName="name" type="text" placeholder="Enter name..." />
</div>
<div>
<br>
<label class="font-weight-bold">Select the Advertistment</label>
<br>
<input (change)="onFileSelect($event)" type="file" />
</div>
<br>
<!--<div *ngIf="imageData">
<img [src]="imageData" [alt]="form.value.name" />
</div>-->
<div>
<label class="font-weight-bold">Upload the Advertistment</label>
<br>
<button type="submit" class="btn btn-success" >Upload Advertistment</button>
</div>
</form>
</body>
create-profile.ts
import { Component, OnInit } from "@angular/core";
import { FormGroup, FormControl } from "@angular/forms";
import { Profile } from "../../models/Profile";
import { ProfileService } from "src/app/services/profile.service";
@Component({
selector: "app-create-profile",
templateUrl: "./create-profile.component.html",
styleUrls: ["./create-profile.component.css"],
})
export class CreateProfileComponent implements OnInit {
form: FormGroup;
profile: Profile;
imageData: string;
constructor(private profileService: ProfileService) {}
ngOnInit(): void {
this.form = new FormGroup({
name: new FormControl(null),
image: new FormControl(null),
});
}
onFileSelect(event: Event) {
const file = (event.target as HTMLInputElement).files[0];
this.form.patchValue({ image: file });
const allowedMimeTypes = ["image/png", "image/jpeg", "image/jpg"];
if (file && allowedMimeTypes.includes(file.type)) {
const reader = new FileReader();
reader.onload = () => {
this.imageData = reader.result as string;
};
reader.readAsDataURL(file);
}
}
onSubmit() {
this.profileService.addProfile(this.form.value.name, this.form.value.image);
this.form.reset();
this.imageData = null;
}
}
profile.service.ts
import { Injectable } from "@angular/core";
import { HttpClient } from "@angular/common/http";
import { map } from "rxjs/operators";
import { Profile } from "../models/Profile";
import { Subject } from "rxjs";
@Injectable({
providedIn: "root",
})
export class ProfileService {
private profiles: Profile[] = [];
private profiles$ = new Subject<Profile[]>();
readonly url = "http://localhost:3000/api/profiles";
constructor(private http: HttpClient) {}
getProfiles() {
this.http
.get<{ profiles: Profile[] }>(this.url)
.pipe(
map((profileData) => {
return profileData.profiles;
})
)
.subscribe((profiles) => {
this.profiles = profiles;
this.profiles$.next(this.profiles);
});
}
getProfilesStream() {
return this.profiles$.asObservable();
}
addProfile(name: string, image: File): void {
const profileData = new FormData();
profileData.append("name", name);
profileData.append("image", image, name);
this.http
.post<{ profile: Profile }>(this.url, profileData)
.subscribe((profileData) => {
const profile: Profile = {
_id: profileData.profile._id,
name: name,
imagePath: profileData.profile.imagePath,
};
this.profiles.push(profile);
this.profiles$.next(this.profiles);
});
}
}
Profile.ts
export interface Profile {
_id: string;
name: string;
imagePath: string;
}
在Angular 7/8/9中
来源链接
使用自举表单
<form>
<div class="form-group">
<fieldset class="form-group">
<label>Upload Logo</label>
{{imageError}}
<div class="custom-file fileInputProfileWrap">
<input type="file" (change)="fileChangeEvent($event)" class="fileInputProfile">
<div class="img-space">
<ng-container *ngIf="isImageSaved; else elseTemplate">
<img [src]="cardImageBase64" />
</ng-container>
<ng-template #elseTemplate>
<img src="./../../assets/placeholder.png" class="img-responsive">
</ng-template>
</div>
</div>
</fieldset>
</div>
<a class="btn btn-danger" (click)="removeImage()" *ngIf="isImageSaved">Remove</a>
</form>
在组件类中
fileChangeEvent(fileInput: any) {
this.imageError = null;
if (fileInput.target.files && fileInput.target.files[0]) {
// Size Filter Bytes
const max_size = 20971520;
const allowed_types = ['image/png', 'image/jpeg'];
const max_height = 15200;
const max_width = 25600;
if (fileInput.target.files[0].size > max_size) {
this.imageError =
'Maximum size allowed is ' + max_size / 1000 + 'Mb';
return false;
}
if (!_.includes(allowed_types, fileInput.target.files[0].type)) {
this.imageError = 'Only Images are allowed ( JPG | PNG )';
return false;
}
const reader = new FileReader();
reader.onload = (e: any) => {
const image = new Image();
image.src = e.target.result;
image.onload = rs => {
const img_height = rs.currentTarget['height'];
const img_width = rs.currentTarget['width'];
console.log(img_height, img_width);
if (img_height > max_height && img_width > max_width) {
this.imageError =
'Maximum dimentions allowed ' +
max_height +
'*' +
max_width +
'px';
return false;
} else {
const imgBase64Path = e.target.result;
this.cardImageBase64 = imgBase64Path;
this.isImageSaved = true;
// this.previewImagePath = imgBase64Path;
}
};
};
reader.readAsDataURL(fileInput.target.files[0]);
}
}
removeImage() {
this.cardImageBase64 = null;
this.isImageSaved = false;
}
我使用的是Angular 5.2.11， 我喜欢Gregor Doroschenko提供的解决方案，但是我注意到上传的文件是零字节的，我必须做一个小小的改变才能让它为我工作。
postFile(fileToUpload: File): Observable<boolean> {
const endpoint = 'your-destination-url';
return this.httpClient
.post(endpoint, fileToUpload, { headers: yourHeadersConfig })
.map(() => { return true; })
.catch((e) => this.handleError(e));
}
下面几行(formData)对我不起作用。
const formData: FormData = new FormData();
formData.append('fileKey', fileToUpload, fileToUpload.name);
https://github.com/amitrke/ngrke/blob/master/src/app/services/fileupload.service.ts
非常简单和最快的方法是使用ng2-file-upload。
通过npm安装ng2-file-upload。NPM I ng2-file-upload——保存
首先在模块中导入模块。
import { FileUploadModule } from 'ng2-file-upload';
Add it to [imports] under @NgModule:
imports: [ ... FileUploadModule, ... ]
标记:
<input ng2FileSelect type="file" accept=".xml" [uploader]="uploader"/>
在你的组件中:
import { FileUploader } from 'ng2-file-upload';
...
uploader: FileUploader = new FileUploader({ url: "api/your_upload", removeAfterUpload: false, autoUpload: true });
这是最简单的用法。要知道所有的权力，这看到演示
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