title: I can not use "this.props.form"
body: <p>sorry I am a beginner for react.
  if I mistake any word or thinking, understand plz. </p>
  
  <p>I make a project with VS2017 react template. 
  and adding the antd from npm. 
  I am testing about the antd form but i see the error. 
  "(TS) 'Readonly&lt;{ children?: ReactNode; }> &amp; Readonly>' can not find 'form' attribute. "</p>
  
  <p>My source is </p>
  
  <pre><code>import { RounteComponentProps } from 'react-router';
  ....
  export class Test extends React.Component&lt;RouteComponentProps&lt;{}&gt;, {}&gt; {
      ....
  
      handleSubmit = (e) =&gt; {
          e.preventDefault();
          this.props.form.validateFields(.....);
      }
      ....
  }
  </code></pre>