在React中提交表单中的数据

Question

Not sure what I'm doing wrong here- this should be really simple, but I can't find the info I'm looking for.

I have a form component and I'm trying to be able to render another component, which is passed props from the form ONLY upon submit. As of right now, the component re-renders on handleChange but does not wait for handleSubmit.

class UserInfo extends React.Component {
  constructor(props) {
    super(props)
    }

    render() {
        return (
        <div>
          <h4>{this.props.name}</h4>
        </div>
      )
    }
} 

class SearchForm extends React.Component {
    constructor(props) {
        super(props)
      this.state = {name: ''}

    this.handleChange= this.handleChange.bind(this);
    this.handleSubmit= this.handleSubmit.bind(this); 
    } 

  handleChange(event) {
      this.setState({ name: event.target.value })
    }   

   handleSubmit(event) {
    event.preventDefault(); 
        this.setState({ name: this.state.name})
        alert(this.state.name + ' was submitted');
    }

    renderUserInfo() {
        return <UserInfo name={this.state.name} />
         } 

    render() {
    return (
        <div>
        <form onSubmit={this.handleSubmit}>
          <label>
            Username: 
            <input type="text" name={this.state.name} onChange={this.handleChange} />
          </label>
          <input type="submit" value="Submit" />
        </form>
       {this.renderUserInfo()}
      </div>
      )
  }
}

Worth noting, this is a simplified version of my problem and I will need "UserInfo" component to be a container eventually, hence the reason for making it a smart component.

Answer 1

Since you're updating the name onChange, the react re-renders the entire component. You can use a submitted flag to check whether the info is submitted or not.

class SearchForm extends React.Component {
    constructor(props) {
        super(props)
      this.state = {
       name: '',
       submitted: false }

    this.handleChange= this.handleChange.bind(this);
    this.handleSubmit= this.handleSubmit.bind(this); 
    } 

  handleChange(event) {
      this.setState({ name: event.target.value })
    }   

   handleSubmit(event) {
    event.preventDefault(); 
        this.setState({ submitted: true })
        alert(this.state.name + ' was submitted');
    }

    renderUserInfo() {
        return <UserInfo name={this.state.name} />
         } 

    render() {
    return (
        <div>
        <form onSubmit={this.handleSubmit}>
          <label>
            Username: 
            <input type="text" name={this.state.name} onChange={this.handleChange} />
          </label>
          <input type="submit" value="Submit" />
        </form>
       {this.state.submitted && this.renderUserInfo()}
      </div>
      )
  }
}