如何将componentWillMount EventEmitter prop传递给React Router 4中的<route>？

Question

我正在尝试使用render <Route>在react-router 4中使用<Route> method将道具传递给我的子组件。看到提到道具的this answer您在{react-router 3中使用的{React.cloneElement(this.props.children, { key: value })}超过componentWillMount。我如何通过EventEmitter生命周期中定义的道具？具体来说，我想使用<Route>对象。

以下是Index.js中有问题的<Route path="/screen3" render={ (props) => <Screen3 eventEmitter={ this.eventEmitter } {...props} /> } /> ：

import React, { Component } from 'react'
import ReactDOM from 'react-dom';
import { Route, BrowserRouter, Switch, Link } from 'react-router-dom';
import { EventEmitter } from 'events';
import Screen3 from './screens/Screen3';

class App extends Component {

  constructor(props) {
    super(props)
    this.state = {
        screenIndex: 1
    }
  }  

  componentWillMount() {
    this.eventEmitter = new EventEmitter()
    this.eventEmitter.addListener("navigateScreen", ({screenIndex}) => {
        this.updateScreen({newScreenIndex: screenIndex})
    })
  }

  updateScreen({newScreenIndex}) {
    this.setState({ screenIndex: newScreenIndex })
  }

  render() {
    return (
        <div className="app">
          <div className="main-content">
            {this.props.children}
          </div>
        </div>
    )
  }
}

ReactDOM.render(
  <BrowserRouter>       
    <App>
        <div>
            <Route path="/screen3" render={ (props) => 
                <Screen3 eventEmitter={ this.eventEmitter } {...props} /> 
            } /> 
        </div>
    </App>
  </BrowserRouter>, 
  document.getElementById('root')
);

完整Index.js：

import React, { Component } from 'react'

class Screen3 extends Component {

  componentWillMount() {
    this.props.eventEmitter.emit("navigateScreen", {screenIndex: 3})
  }

  render() {
    return (
      <div className="screen screen3">
        <h1>SCREEN 3 DATA</h1>
      </div>
    )

  }

在我的Screen3.js组件中：

export default Screen3

}

eventEmitter

当我在Screen3组件中执行console.log(this.props.eventEmitter)时，var postsAndTagCounts = context.Posts .Select(p => new { PostId = p.Id, TagCount = p.Tags.Count() }) .OrderByDescending(p => p.Tags.Count()) .ToList(); 道具未定义。有什么想法吗？