在react中将变量从一个组件发送到另一个组件

// 父组件
class ParentComponent extends React.Component {
  render() {
    const variable = "Hello, World!";
    return <ChildComponent variable={variable} />;
  }
}

// 子组件
class ChildComponent extends React.Component {
  render() {
    return <div>{this.props.variable}</div>;
  }
}

// 父组件
class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      variable: ""
    };
  }

  updateVariable = (newVariable) => {
    this.setState({ variable: newVariable });
  }

  render() {
    return (
      <div>
        <ChildComponent variable={this.state.variable} updateVariable={this.updateVariable} />
      </div>
    );
  }
}

// 子组件
class ChildComponent extends React.Component {
  handleChange = (event) => {
    this.props.updateVariable(event.target.value);
  }

  render() {
    return (
      <div>
        <input type="text" value={this.props.variable} onChange={this.handleChange} />
      </div>
    );
  }
}