title: how to post a form with payload in angular 2?
body: <p>I am playing with angular 2, try to create a sample app that upload a file.
  Have below view and component, when i click submit, i don`t see any request is coming out from browser. </p>
  
  <p>if i add (ngSubmit)="onSubmit()" to form, i can see onSubmit is invoked, but i don`t see anything pass into it. </p>
  
  <p><strong><em>Question: what is the right way to get proper binding so that i can have a valid file upload form?</em></strong></p>
  
  <p>Template:</p>
  
  <pre><code>&lt;form action="api/upload" method="POST" enctype="multipart/form-data" class="btn-group" role="group"&gt;
      &lt;input type="file" class="btn btn-lg btn-default" required&gt;
      &lt;input type="submit" value="Upload" class="btn btn-lg btn-primary upload-btn"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <hr>
  
  <p>Component:</p>
  
  <pre><code>import {Component} from 'angular2/core';
  import {FORM_DIRECTIVES}    from 'angular2/common';
  
  @Component({
      selector: 'my-app',
      directives: [FORM_DIRECTIVES],
      template: 'path-to-template'
  })
  
  export class AppComponent {
      onSubmit(e) {
          // TODO: get payload from form and upload to server
          console.log(e);
      }
  }
  </code></pre>