react解决 Cannot read property 'st

报错描述

点击按钮，触发chargeFunc函数，很简单的一个操作，却报了如下错误

报错内容如下

解决办法

chargeFunc(){}改成chargeFunc= (e) => {}

错误写法

class Operation extends React.PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      file: "2112",
    };
  }
  render() {
    return (
      <Fragment>
        <Button key="submit" type="primary" onClick={this.chargeFunc}>
          确定{" "}
        </Button>
      </Fragment>
    );
  }
  chargeFunc() {
    console.log("file为", this.state.file);
  }
}

export default Operation;

正确写法

class Operation extends React.PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      file: "2112",
    };
  }
  render() {
    return (
      <Fragment>
        <Button key="submit" type="primary" onClick={this.chargeFunc}>
          确定{" "}
        </Button>
      </Fragment>
    );
  }
  chargeFunc= (e) => {
    console.log("file为",this.state.file);
  }

}

export default Operation;