反应组件错误 Cannot read 属性 of undefined

Question

我是 React 的新手，我创建了这样的组件；

export default class CartoviewDrawer extends React.Component {

    constructor(props) {
        super(props);
        this.state = {open: false};
    }

    _handleToggle() {
        let open = this.state.open;
        this.setState({open: !open})
    }

    render() {
        return (
            <div>
                {/*<RaisedButton*/}
                {/*label="Toggle Drawer"*/}
                {/*onTouchTap={this.handleToggle}*/}
                {/*/>*/}
                <IconButton tooltip="Toggle Drawer"
                            onTouchTap={this._handleToggle}
                >
                    <i className="material-icons">list</i>
                </IconButton>
                <IconButton iconClassName="muidocs-icon-custom-github"/>
                <Drawer open={this.state.open}>
                    <MenuItem>Menu Item</MenuItem>
                    <MenuItem>Menu Item 2</MenuItem>
                </Drawer>
            </div>
        );
    }
}

在另一个文件中，我通过 ;

导入了这个组件

import CartoviewDrawer from './cartoview_drawer'

然后我使用这个组件:

React.createElement(AppBar,toolbarOptions,React.createElement(CartoviewDrawer))

但是当我点击浏览器控制台中的图标错误并且没有出现抽屉时。错误：

Uncaught TypeError: Cannot read property 'open' of undefined

Answer 1

您缺少与 'this' 的绑定将 onTouchTap 调用更改为此：

onTouchTap={this._handleToggle.bind(this)}

Answer 2

在组件构造函数中添加绑定：

constructor(props) {
  super(props);
  ...
  this._handleToggle= this._handleToggle.bind(this);
}

反应组件错误 Cannot read 属性 of undefined

react component error Cannot read property of undefined

jsx

reactjs

material-ui