React组件呈现Child组件

Question

我的代码出了点问题：

在这种情况下，

1标题不显示

import React from 'react';
import {Link} from 'react-router';

import CurrentUser from './../services/current-user.js';
import HeaderWithoutLogin from './header-without-login.js';
import HeaderWithLogin from './header-with-login.js';

let Header = React.createClass({
    render: () => {
        var Child = CurrentUser.isLoggedIn()
            ? HeaderWithLogin
            : HeaderWithoutLogin;
        return <div>{Child}</div>;
    }
});

export default Header;

2在这种情况下我收到了一个错误：＆＃34;无法读取属性＆＃39; state＆＃39;未定义＆＃34;

import React from 'react';
import {Link} from 'react-router';

import CurrentUser from './../services/current-user.js';
import HeaderWithoutLogin from './header-without-login.js';
import HeaderWithLogin from './header-with-login.js';

let Header = React.createClass({
    render: () => {
        if (CurrentUser.isLoggedIn()) {
            return <HeaderWithLogin/>;
        }
        return <HeaderWithoutLogin/>;
    }
});

export default Header;

我需要如何使用我的逻辑？我的意思是返回并呈现关于语句的不同观点