OnChange Typescript输入

Question

我希望能够在从输入（文件）中选择文件时触发更改。我希望触发事件将文本框设置为文件的名称。

我正在使用HTML5，Typescript和Angular2。我无法弄清楚或找到一个确切如何产生我所追求的行为的例子。

请参阅下面的代码：

component.ts

import { Component } from '@angular/core';
import { Http } from '@angular/http';
import { Headers, RequestOptions } from '@angular/http';

@Component({
    selector: 'testConnection',
    // ignore error on require
    template: require('./testConnection.component.html')
})
export class TestConnectionComponent {
    public http: Http;
    public requestData: RequestData;


    public constructor(http: Http) {
        this.http = http;

        (<HTMLInputElement>document.getElementById('fileInput')).onchange = (ev: Event) => {
            var fileInput = (<HTMLInputElement>ev.srcElement).files[0];

            var fileTextbox = (<HTMLInputElement>document.getElementById('fileTextbox'));
            fileTextbox.value = fileInput.name;
        }
    }


    public testButtonClick() {

        // Iniatialise Request object
        let request: RequestData;
        request = { "CountryCode": "", "SiteIDList": "" };

        // Get site(s)
        var siteIdList = (<HTMLInputElement>document.getElementById('siteIDInput')).value;

        // Get selected country
        var countryCode = (<HTMLInputElement>document.getElementById('countryDropdown')).value;

        // Veryify contents is just site ids. 
        // TODO
        request.CountryCode = countryCode;
        request.SiteIDList = siteIdList;


        // Set Http POST options
        let headers = new Headers({ 'Content-Type': 'application/json' });
        let options = new RequestOptions({ headers: headers });

        // Call Api with test connection data 
        this.http
            .post('/api/TestConnection/TestConnection', JSON.stringify(request), options)
            .subscribe(data => {
                // alert request ok
                alert('ok');
            }, error => {
                // Log error
                console.log(error.json());
            });
    }
}

interface RequestData {
    SiteIDList: string;
    CountryCode: string;
}

component.html

<h2>Test Site Connection</h2>

<p>This will allow you to check the connectivity of a set of sites by either individually or uploading a CSV file of Site IDs.</p>
<br />
<div class="panel panel-primary">
    <div class="panel-heading">
        <h3 class="panel-title">Manual Test</h3>
    </div>
    <div class="panel-body">
        <p>
            Select the country and the sites you want to test.
        </p>
        <ul>
            <li>Multiple sites can be selected using commas (,).</li>
            <li>you can see results in the Site Connection Results tab</li>
        </ul>
        <br />
        <!--Replace with lookup to enabled countries-->
        <div class="form-group col-lg-4">
            <div class="col-lg-6">
                <select class="form-control" id="countryDropdown">
                    <option>Select Country</option>
                    <option>US</option>
                    <option>SG</option>
                    <option>NL</option>
                </select>
            </div>
        </div>
        <div>
            <div class="col-lg-4">
                <input type="text" class="form-control" placeholder="SiteID(s)" id="siteIDInput" />
            </div>
            <button class="btn btn-primary" (click)="testButtonClick()">Test</button>
        </div>
    </div>
</div>

<div class="panel panel-success">
    <div class="panel-heading">
        <h3 class="panel-title">Upload file</h3>
    </div>
    <div class="panel-body">
        <div>
            <p>Upload a CSV file of sites to test all at once.</p>
            <br />
            <div class="col-lg-4">
                <input type="text" class="col-lg-4 form-control" id="fileTextbox" disabled/>
            </div>
            <label class="btn btn-primary">
                Browse <input type="file" id="fileInput" style="display:none;" onchange="{ setFileName() }"/>
            </label>
            <button class="btn btn-primary" (click)="searchButtonClick()">Test</button>
        </div>
    </div>
</div>

<div class="modal">
    <div class="modal-dialog">
        <div class="modal-content">
            <div class="modal-header">
                <button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
                <h4 class="modal-title">Modal title</h4>
            </div>
            <div class="modal-body">
                <p>One fine body…</p>
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                <button type="button" class="btn btn-primary">Save changes</button>
            </div>
        </div>
    </div>
</div>

Answer 1

尝试使用（更改）事件绑定

Metadata cached = getHeaders().get(Metadata.Key.of("testID", Metadata.ASCII_STRING_MARSHALLER)));
headers.merge(cached);

Answer 2

如果您需要在> 上传之前检索文件名，可以这样做：

@Component({
    selector: 'my-app',
    template: `
      <div>
        <input type="file" (change)="onChange($event)"/>
      </div>
      <p>Filename : {{filename}}</p>
    `,
    providers: []
})
export class AppComponent {
  filename: string;
  constructor() { }

  onChange(event) {
    this.filename = event.srcElement.files[0].name;
  }
}

这是 working plunker