如何从表单组件获取状态/值? [英] How to get state / value from form component?

问题描述

考虑具有如下形式的组件:

Consider having form component like:

export default class Form extends React.Component {
  constructor (props) {
    this.state = { email: '' }
    this.onChange = this.onChange.bind(this)
  }

  onChange(event) {
    this.setState({ email: event.target.value })
  } 

  render () {
    return (
      <div>
        <h2>{this.props.title}</h2>
        <form className={cx('Form')} onSubmit={this.props.onSubmit}>
          <input className={cx('Form-email')} type='email' placeholder='email' value={this.state.email} onChange={this.onChange} />
          <input className={cx('Form-btn')} type='submit' value='sign up' />
        </form>
      </div>
    )
  }
}

然后我将在应用程序中的其他位置使用此<Form onSubmit={this.someFunction} />组件，让我们在HomePage组件内部进行假设.在该主页中，我将有this.someFunction会在表单到达顶点时执行，如何将表单的值/状态传递给它?

I would then use this <Form onSubmit={this.someFunction} /> component elsewhere within my app, lets assume inside HomePage component. Inside that home page I would have this.someFunction that executes when form is summited, how can I pass form value / state to it?

推荐答案

在您的组件中创建一个回调，该回调将以状态为参数调用发送到Form的函数.

Create a callback in your component that will call the function sent to Form with the state as parameter.

export default class Form extends React.Component {
    constructor (props) {
        this.state = { email: '' }
        this.onChange = this.onChange.bind(this)
        this.onSubmit = this.onSubmit.bind(this)
    }

    onChange(event) {
        this.setState({ email: event.target.value })
    } 

    onSubmit() {
        this.props.onSubmit(this.state);
    } 

    render () {
        return (
            <div>
                <h2>{this.props.title}</h2>
                <form className={cx('Form')} onSubmit={this.onSubmit}>
                    <input className={cx('Form-email')} type='email' placeholder='email' value={this.state.email} onChange={this.onChange} />
                    <input className={cx('Form-btn')} type='submit' value='sign up' />
                </form>
            </div>
        )
    }
}

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