我知道这是一个非常普遍的问题，但我在Angular 2中上传文件失败了。 我试过了
1) http://valor-software.com/ng2-file-upload/
2) http://ng2-uploader.com/home
.．.但失败了。有人在Angular中上传过文件吗?你用了什么方法?怎么做呢?如果提供了任何示例代码或演示链接，将非常感谢。
当前回答
这个简单的解决方案对我很有效:file-upload.component.html
<div>
<input type="file" #fileInput placeholder="Upload file..." />
<button type="button" (click)="upload()">Upload</button>
</div>
然后在组件中直接使用XMLHttpRequest进行上传。
import { Component, OnInit, ViewChild } from '@angular/core';
@Component({
selector: 'app-file-upload',
templateUrl: './file-upload.component.html',
styleUrls: ['./file-upload.component.css']
})
export class FileUploadComponent implements OnInit {
@ViewChild('fileInput') fileInput;
constructor() { }
ngOnInit() {
}
private upload() {
const fileBrowser = this.fileInput.nativeElement;
if (fileBrowser.files && fileBrowser.files[0]) {
const formData = new FormData();
formData.append('files', fileBrowser.files[0]);
const xhr = new XMLHttpRequest();
xhr.open('POST', '/api/Data/UploadFiles', true);
xhr.onload = function () {
if (this['status'] === 200) {
const responseText = this['responseText'];
const files = JSON.parse(responseText);
//todo: emit event
} else {
//todo: error handling
}
};
xhr.send(formData);
}
}
}
如果使用dotnet core，参数名必须与from字段名匹配。本例中的文件:
[HttpPost("[action]")]
public async Task<IList<FileDto>> UploadFiles(List<IFormFile> files)
{
return await _binaryService.UploadFilesAsync(files);
}
这个答案抄袭了http://blog.teamtreehouse.com/uploading-files-ajax
编辑: 上传后，您必须清除文件上传，以便用户可以选择一个新文件。与其使用XMLHttpRequest，不如使用fetch:
private addFileInput() {
const fileInputParentNative = this.fileInputParent.nativeElement;
const oldFileInput = fileInputParentNative.querySelector('input');
const newFileInput = document.createElement('input');
newFileInput.type = 'file';
newFileInput.multiple = true;
newFileInput.name = 'fileInput';
const uploadfiles = this.uploadFiles.bind(this);
newFileInput.onchange = uploadfiles;
oldFileInput.parentNode.replaceChild(newFileInput, oldFileInput);
}
private uploadFiles() {
this.onUploadStarted.emit();
const fileInputParentNative = this.fileInputParent.nativeElement;
const fileInput = fileInputParentNative.querySelector('input');
if (fileInput.files && fileInput.files.length > 0) {
const formData = new FormData();
for (let i = 0; i < fileInput.files.length; i++) {
formData.append('files', fileInput.files[i]);
}
const onUploaded = this.onUploaded;
const onError = this.onError;
const addFileInput = this.addFileInput.bind(this);
fetch('/api/Data/UploadFiles', {
credentials: 'include',
method: 'POST',
body: formData,
}).then((response: any) => {
if (response.status !== 200) {
const error = `An error occured. Status: ${response.status}`;
throw new Error(error);
}
return response.json();
}).then(files => {
onUploaded.emit(files);
addFileInput();
}).catch((error) => {
onError.emit(error);
});
}
https://github.com/yonexbat/cran/blob/master/cranangularclient/src/app/file-upload/file-upload.component.ts
其他回答
尽量不要设置options参数
这个http post(美元(this。apiEndPoint), formData)
并且确保你没有在你的Http工厂中设置globalHeaders。
这个简单的解决方案对我很有效:file-upload.component.html
<div>
<input type="file" #fileInput placeholder="Upload file..." />
<button type="button" (click)="upload()">Upload</button>
</div>
然后在组件中直接使用XMLHttpRequest进行上传。
import { Component, OnInit, ViewChild } from '@angular/core';
@Component({
selector: 'app-file-upload',
templateUrl: './file-upload.component.html',
styleUrls: ['./file-upload.component.css']
})
export class FileUploadComponent implements OnInit {
@ViewChild('fileInput') fileInput;
constructor() { }
ngOnInit() {
}
private upload() {
const fileBrowser = this.fileInput.nativeElement;
if (fileBrowser.files && fileBrowser.files[0]) {
const formData = new FormData();
formData.append('files', fileBrowser.files[0]);
const xhr = new XMLHttpRequest();
xhr.open('POST', '/api/Data/UploadFiles', true);
xhr.onload = function () {
if (this['status'] === 200) {
const responseText = this['responseText'];
const files = JSON.parse(responseText);
//todo: emit event
} else {
//todo: error handling
}
};
xhr.send(formData);
}
}
}
如果使用dotnet core，参数名必须与from字段名匹配。本例中的文件:
[HttpPost("[action]")]
public async Task<IList<FileDto>> UploadFiles(List<IFormFile> files)
{
return await _binaryService.UploadFilesAsync(files);
}
这个答案抄袭了http://blog.teamtreehouse.com/uploading-files-ajax
编辑: 上传后，您必须清除文件上传，以便用户可以选择一个新文件。与其使用XMLHttpRequest，不如使用fetch:
private addFileInput() {
const fileInputParentNative = this.fileInputParent.nativeElement;
const oldFileInput = fileInputParentNative.querySelector('input');
const newFileInput = document.createElement('input');
newFileInput.type = 'file';
newFileInput.multiple = true;
newFileInput.name = 'fileInput';
const uploadfiles = this.uploadFiles.bind(this);
newFileInput.onchange = uploadfiles;
oldFileInput.parentNode.replaceChild(newFileInput, oldFileInput);
}
private uploadFiles() {
this.onUploadStarted.emit();
const fileInputParentNative = this.fileInputParent.nativeElement;
const fileInput = fileInputParentNative.querySelector('input');
if (fileInput.files && fileInput.files.length > 0) {
const formData = new FormData();
for (let i = 0; i < fileInput.files.length; i++) {
formData.append('files', fileInput.files[i]);
}
const onUploaded = this.onUploaded;
const onError = this.onError;
const addFileInput = this.addFileInput.bind(this);
fetch('/api/Data/UploadFiles', {
credentials: 'include',
method: 'POST',
body: formData,
}).then((response: any) => {
if (response.status !== 200) {
const error = `An error occured. Status: ${response.status}`;
throw new Error(error);
}
return response.json();
}).then(files => {
onUploaded.emit(files);
addFileInput();
}).catch((error) => {
onError.emit(error);
});
}
https://github.com/yonexbat/cran/blob/master/cranangularclient/src/app/file-upload/file-upload.component.ts
我已经上传文件使用引用。以这种方式上传文件不需要包。
//要写入.ts文件的代码
@ViewChild("fileInput") fileInput;
addFile(): void {
let fi = this.fileInput.nativeElement;
if (fi.files && fi.files[0]) {
let fileToUpload = fi.files[0];
this.admin.addQuestionApi(fileToUpload)
.subscribe(
success => {
this.loading = false;
this.flashMessagesService.show('Uploaded successfully', {
classes: ['alert', 'alert-success'],
timeout: 1000,
});
},
error => {
this.loading = false;
if(error.statusCode==401) this.router.navigate(['']);
else
this.flashMessagesService.show(error.message, {
classes: ['alert', 'alert-danger'],
timeout: 1000,
});
});
}
}
//服务中要编写的代码。ts文件
addQuestionApi(fileToUpload: any){
var headers = this.getHeadersForMultipart();
let input = new FormData();
input.append("file", fileToUpload);
return this.http.post(this.baseUrl+'addQuestions', input, {headers:headers})
.map(response => response.json())
.catch(this.errorHandler);
}
//用HTML编写的代码
<input type="file" #fileInput>
在Angular 2+中，让Content-Type为空是非常重要的。如果您将“内容类型”设置为“multipart/form-data”，则上传将无法工作!
upload.component.html
<input type="file" (change)="fileChange($event)" name="file" />
upload.component.ts
export class UploadComponent implements OnInit {
constructor(public http: Http) {}
fileChange(event): void {
const fileList: FileList = event.target.files;
if (fileList.length > 0) {
const file = fileList[0];
const formData = new FormData();
formData.append('file', file, file.name);
const headers = new Headers();
// It is very important to leave the Content-Type empty
// do not use headers.append('Content-Type', 'multipart/form-data');
headers.append('Authorization', 'Bearer ' + 'eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9....');
const options = new RequestOptions({headers: headers});
this.http.post('https://api.mysite.com/uploadfile', formData, options)
.map(res => res.json())
.catch(error => Observable.throw(error))
.subscribe(
data => console.log('success'),
error => console.log(error)
);
}
}
}
Angular 2对上传文件提供了很好的支持。不需要第三方库。
<input type="file" (change)="fileChange($event)" placeholder="Upload file" accept=".pdf,.doc,.docx">
fileChange(event) {
let fileList: FileList = event.target.files;
if(fileList.length > 0) {
let file: File = fileList[0];
let formData:FormData = new FormData();
formData.append('uploadFile', file, file.name);
let headers = new Headers();
/** In Angular 5, including the header Content-Type can invalidate your request */
headers.append('Content-Type', 'multipart/form-data');
headers.append('Accept', 'application/json');
let options = new RequestOptions({ headers: headers });
this.http.post(`${this.apiEndPoint}`, formData, options)
.map(res => res.json())
.catch(error => Observable.throw(error))
.subscribe(
data => console.log('success'),
error => console.log(error)
)
}
}
使用@angular/core": "~2.0.0"和@angular/http: "~2.0.0"
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