React中的事件处理程序

Question

我试图onChange在Component上写一个(curried？)事件处理程序,它将接收一个key参数,让它知道要更新的状态对象中的哪个键.代码不会编译,说'key' is not defined.

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      firstName: null,
      lastName: null
    }
    this.handleChange = this.handleChange.bind(this);
  }

  handleChange = (key) = (event) => {
    console.log(key, event);
  }

  render() {
    return (
      <div>

        <form>
          <input onChange={this.handleChange('firstName')} value={this.state.firstName} />
          <input onChange={this.handleChange('lastName')} value={this.state.firstName} />
        </form>

        {JSON.stringify(this.state, null, 4)}
      </div>
    );
  }
}

Answer 1

您必须同时传递event和key处理程序OnChange。

做这个

<input onChange={this.handleChange.bind(this,'firstName')} value={this.state.firstName} />

并且onChange应该是

 handleChange = (key, event) => {
    console.log(key, event);
  }

这将允许传递event和 ，并且该函数将起作用。key