Angular 4 中的文件上传

Question

当我尝试安装时 “npm install ng2-file-upload --save” 在我的 Angular 4 应用程序中它抛出

UNMET PEER DEPENDENCY @4.1.0
UNMET PEER DEPENDENCY @4.1.0
`-- ng2-file-upload@1.2.1

上传不工作 我的应用程序抛出

"无法绑定到 'uploader'，因为它不是 'input' 的已知属性"

这是我的 HTML

<input type="file" ng2FileSelect [uploader]="upload" multiple formControlName="file" id="file"/>

及其组件

import { FileUploadModule } from 'ng2-file-upload/ng2-file-upload';   
import { FileSelectDirective, FileUploader } from 'ng2-file-upload/ng2-file-
upload';

export class PersonalInfoComponent implements OnInit
{
    public upload:FileUploader= new FileUploader({url:""});
}

父模块

import { FileUploadModule } from 'ng2-file-upload/ng2-file-upload';

@NgModule({

imports: [
..
....
..
FileUploadModule
],

export class RegistrationModule { }

我没有在 AppModule（祖父模块）中导入/更改任何内容。

有人可以帮我解决这个问题吗...

Answer 1

从primeng导入文件上传或使用简单的文件上传器

HTML

  <p-fileUpload name="myfile[]"  customUpload="true" 
     (uploadHandler)="uploadSuiteForRelease($event)" auto="auto"></p-fileUpload> 

TS

 var data = new FormData();
        let index: number = 0;
        if (this.files != undefined)
        {
            for (let file of this.files.files)
            {
                data.append("myFile" + index, file);
                ++index;
            }
        }
     data.append('viewModel', JSON.stringify(<<data model that needs to be 
     sent with request>>));

请求发送此数据 return this._httpClient.post('api/controller', data);

服务器

  [HttpPost]
        public async Task<IHttpActionResult> Post()
        {
            HttpPostedFile httpPostedFile = null;
            var viewModel = JsonConvert.DeserializeObject<ReleasesViewModel>(HttpContext.Current.Request["viewModel"]);
            if (viewModel != null)
            {
                if (HttpContext.Current.Request.Files.AllKeys.Any())
                {
                    var cnt = HttpContext.Current.Request.Files.Count;
                    for (int i = 0; i < cnt; i++)
                    {
                        httpPostedFile = HttpContext.Current.Request.Files["myFile" + i];
                    }
                }
            }
        }

Answer 2

您不需要外部库来执行此操作，请查看以下示例代码

@Component({
    selector: 'app-root',
    template: '<div>'
        + '<input type="file" (change)="upload($event)">'
        + '</div>',
})

export class AppComponent {

    constructor(private _service: commonService) { }

    upload(event: any) {
        let files = event.target.files;
        let fData: FormData = new FormData;

        for (var i = 0; i < files.length; i++) {
            fData.append("file[]", files[i]);
        }
        var _data = {
            filename: 'Sample File',
            id: '0001'
        }

        fData.append("data", JSON.stringify(_data));

        this._service.uploadFile(fData).subscribe(
            response => this.handleResponse(response),
            error => this.handleError(error)
        )
    }
    handleResponse(response: any) {
        console.log(response);
    }
    handleError(error: string) {
        console.log(error);
    }
}

More info

Answer 3

HTML：

<input type="file" (change)="onFileChange($event)" id="file">

TS：

@Component({
  ......
})

export class myComponent{

    form: FormGroup;

    contructor(fb: FormGroup){
       form: fb.group({file: null});
    }

 //fVals comes from HTML Form -> (ngSubmit)="postImage(form.value)" 
    postImage(fVals){
      let body = new FormData();
      body.append('file', formValues.file);

      let httpRequest = httpclient.post(url, body);
      httpRequest.subscribe((response) =>{
         //..... handle response here
      },(error) => {
         //.....handle errors here
      });
   }

   onFileChange(event) {
     if(event.target.files.length > 0) {
       let file = event.target.files[0];
       this.form.get('file').setValue(file);
     }
   }
}

Answer 4

我认为我们不需要一些额外的库

onFileChange(event){
   let files = event.target.files; 
   this.saveFiles(files);
    }
@HostListener('dragover', ['$event']) onDragOver(event) {
    this.dragAreaClass = "droparea";
    event.preventDefault();
}
@HostListener('dragenter', ['$event']) onDragEnter(event) {
    this.dragAreaClass = "droparea";
    event.preventDefault();
}
@HostListener('dragend', ['$event']) onDragEnd(event) {
    this.dragAreaClass = "dragarea";
    event.preventDefault();
}
@HostListener('dragleave', ['$event']) onDragLeave(event) {
    this.dragAreaClass = "dragarea";
    event.preventDefault();
}
@HostListener('drop', ['$event']) onDrop(event) {   
    this.dragAreaClass = "dragarea";           
    event.preventDefault();
    event.stopPropagation();
    var files = event.dataTransfer.files;
    this.saveFiles(files);
}

现在我们已经准备好通过拖放以及单击链接按钮上传文件并上传带有文件的额外数据。

在此处查看完整文章Angular 4 upload files with data and web api by drag & drop

Answer 5

在没有插件的情况下在 Angular 4 中上传图片 这是可能值得一试的文章。 Upload images in Angular 4 without a plugin

强调以下几点：

1. 使用 .request() 方法代替 .post
2. 将 formData 直接发送到正文中。
3. 自定义标头项并构造新的 RequestOptions 对象。
4. 要发送带有图像内容的 formData，您必须删除 Content-Type 标头。

Answer 6

常见的解决方案是创建像shared module 这样的新模块。您只需要创建共享模块，例如 这个并在app.module文件中导入共享模块

import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';

import { FileSelectDirective, FileDropDirective } from 'ng2-file-upload';
import { FileUploadModule } from 'ng2-file-upload/ng2-file-upload';

@NgModule({
     imports: [ FileUploadModule],  
     declarations: [ ],
     exports :[ FileSelectDirective, FileDropDirective, FormsModule,
               FileUploadModule],
})
export class SharedModule { }

只需像这样在你的 app.module 中导入 share.module。

import { NgModule } from '@angular/core';
import { SharedModule} from '../shared/shared.module';

@NgModule({
    imports: [SharedModule],
    declarations: [],
    exports :[],
   })
export class AppModule { }

看看 Angular 4 中的延迟加载