是什么导致我的ASP.NET Core React with Redux Project中的“元素类型无效”错误？

Question

我正在使用ASP.NET Core项目，该项目使用Visual Studio内置的React with Redux模板以及界面的Material-UI库。目前，我正在创建一个AppBar，当我尝试运行解决方案时，出现以下错误：

  

元素类型无效：预期为字符串（对于内置组件）   或类/函数（用于复合组件）但得到了：对象。

我进行了一些搜索，并提出了一些建议，指出该组件的一部分未导出，但是，这使我无处可寻。

我将此错误缩小到Appbar的特定部分，即：

<InputBase placeholder="Search…" classes={{ root: classes.inputRoot, input: classes.inputInput }} />

如果我删除了上面的代码行，则一切正常。这是我的AppBar at the moment

的完整代码

import React from 'react';
import PropTypes from 'prop-types';
import AppBar from '@material-ui/core/AppBar';
import Toolbar from '@material-ui/core/Toolbar';
import IconButton from '@material-ui/core/IconButton';
import Typography from '@material-ui/core/Typography';
import InputBase from '@material-ui/core/InputBase';    
import Badge from '@material-ui/core/Badge';
import MenuItem from '@material-ui/core/MenuItem';
import Menu from '@material-ui/core/Menu';
import { fade } from '@material-ui/core/styles/colorManipulator';
import { withStyles } from '@material-ui/core/styles';
import MenuIcon from '@material-ui/icons/Menu';
import SearchIcon from '@material-ui/icons/Search';
import AccountCircle from '@material-ui/icons/AccountCircle';
import MailIcon from '@material-ui/icons/Mail';
import NotificationsIcon from '@material-ui/icons/Notifications';
import MoreIcon from '@material-ui/icons/MoreVert';

const styles = theme => ({
    root: {
        width: '100%',
    },
    grow: {
        flexGrow: 1,
    },
    menuButton: {
        marginLeft: -12,
        marginRight: 20,
    },
    title: {
        display: 'none',
        [theme.breakpoints.up('sm')]: {
            display: 'block',
        },
    },
    search: {
        position: 'relative',
        borderRadius: theme.shape.borderRadius,
        backgroundColor: fade(theme.palette.common.white, 0.15),
        '&:hover': {
            backgroundColor: fade(theme.palette.common.white, 0.25),
        },
        marginRight: theme.spacing.unit * 2,
        marginLeft: 0,
        width: '100%',
        [theme.breakpoints.up('sm')]: {
            marginLeft: theme.spacing.unit * 3,
            width: 'auto',
        },
    },
    searchIcon: {
        width: theme.spacing.unit * 9,
        height: '100%',
        position: 'absolute',
        pointerEvents: 'none',
        display: 'flex',
        alignItems: 'center',
        justifyContent: 'center',
    },
    inputRoot: {
        color: 'inherit',
        width: '100%',
    },
    inputInput: {
        paddingTop: theme.spacing.unit,
        paddingRight: theme.spacing.unit,
        paddingBottom: theme.spacing.unit,
        paddingLeft: theme.spacing.unit * 10,
        transition: theme.transitions.create('width'),
        width: '100%',
        [theme.breakpoints.up('md')]: {
            width: 200,
        },
    },
    sectionDesktop: {
        display: 'none',
        [theme.breakpoints.up('md')]: {
            display: 'flex',
        },
    },
    sectionMobile: {
        display: 'flex',
        [theme.breakpoints.up('md')]: {
            display: 'none',
        },
    },
});

class Appbar extends React.Component {
    state = {
        anchorEl: null
    };
    handleProfileMenuOpen = event => {
        this.setState({ anchorEl: event.currentTarget });
    };
    render() {
        const { classes } = this.props;
        const { anchorEl } = this.state;
        const isMenuOpen = Boolean(anchorEl);
        return (
            <div className={classes.root}>
                <AppBar position="static">
                    <Toolbar>
                        <IconButton className={classes.menuButton} color="inherit" aria-label="Open drawer">
                            <MenuIcon />
                        </IconButton>
                        <Typography className={classes.title} variant="h6" color="inherit" noWrap>
                            My Brand
                        </Typography>
                        <div className={classes.search}>
                            <div className={classes.searchIcon}>
                                <SearchIcon />
                            </div>
                            <InputBase placeholder="Search…" classes={{ root: classes.inputRoot, input: classes.inputInput }} />
                        </div>
                        <div className={classes.grow} />
                        <div className={classes.sectionDesktop}>

                            <IconButton
                                aria-owns={isMenuOpen ? 'material-appbar' : undefined}
                                aria-haspopup="true"
                                onClick={this.handleProfileMenuOpen}
                                color="inherit">
                                <AccountCircle />
                            </IconButton>
                        </div>

                    </Toolbar>
                </AppBar>
            </div>
        );
    }
}

Appbar.propTypes = {
    classes: PropTypes.object.isRequired,
};

export default withStyles(styles)(Appbar);

如上所述，删除InputBase行会阻止错误，我只能认为这可能与classes列表部分有关？

有人可以协助解决此错误吗？