从<输入类型=“文件">上传文件 [英] File upload from &lt;input type=&quot;file&quot;&gt;

问题描述

使用 angular 2 beta，我似乎无法让 <input type="file"> 工作.

使用诊断，我可以看到其他type的双向绑定，例如text.

{{诊断}}<div class="form-group"><label for="fileupload">上传</label><input type="file" class="form-control" [(ngModel)]="model.fileupload">

</表单>

在我的 TypeScript 文件中，我有以下诊断行:

get diagnostic() { return JSON.stringify(this.model);}

会不会是不是JSON的问题?值为 null.

我无法真正验证 input 的值.У尽管选择文件..."旁边的文本更新了，但由于某种原因，我看不到 DOM 中的差异.

解决方案

我认为它不受支持.如果您查看此 DefaultValueAccessor 指令(请参阅 https://github.com/angular/angular/blob/master/modules/angular2/src/common/forms/directives/default_value_accessor.ts#L23).您将看到用于更新绑定元素的值是 $event.target.value.

这不适用于类型为 file 的输入的情况，因为可以使用 $event.srcElement.files 代替文件对象.

有关更多详细信息，您可以查看此 plunkr:https://plnkr.co/edit/ozZqbxIorjQW15BrDFrg?p=信息:

@Component({选择器:'我的应用'，模板:`<div><input type="file" (change)="onChange($event)"/>

`，提供者:[上传服务]})导出类 AppComponent {onChange(事件){var 文件 = event.srcElement.files;控制台日志(文件)；}}

Using angular 2 beta, I cannot seem to get an <input type="file"> to work.

Using diagnostic, I can see two-way binding for other types such as text.

<form>
    {{diagnostic}}
    <div class="form-group">
        <label for="fileupload">Upload</label>
        <input type="file" class="form-control" [(ngModel)]="model.fileupload">
    </div>
</form>

In my TypeScript file, I have the following diagnostic line:

get diagnostic() { return JSON.stringify(this.model); }

Could it be that it is the issue of not being JSON? The value is null.

I cannot really verify the value of the input. Уven though the text next to "Choose file ..." updates, I cannot see differences in the DOM for some reason.

解决方案

I think that it's not supported. If you have a look at this DefaultValueAccessor directive (see https://github.com/angular/angular/blob/master/modules/angular2/src/common/forms/directives/default_value_accessor.ts#L23). You will see that the value used to update the bound element is $event.target.value.

This doesn't apply in the case of inputs with type file since the file object can be reached $event.srcElement.files instead.

For more details, you can have a look at this plunkr: https://plnkr.co/edit/ozZqbxIorjQW15BrDFrg?p=info:

@Component({
  selector: 'my-app',
  template: `
    <div>
      <input type="file" (change)="onChange($event)"/>
    </div>
  `,
  providers: [ UploadService ]
})
export class AppComponent {
  onChange(event) {
    var files = event.srcElement.files;
    console.log(files);
  }
}

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