Reactjs - 将状态值从一个组件传递到另一个组件

Question

我有两个组件SideNav和Dashboard(两个在不同的js文件中).SideNav将selectbox作为过滤器.我必须将一个数组从Dashboard组件传递给Sidebar组件.此数组必须作为选择框的值(在sidenav组件内)给出.

PS如果我在两个不同的JS文件中定义了两个不同的组件类,那将是什么情况.例如HomeComponent/Home.js - >父组件Dashboard/Dashboard.js - >子组件我正在对"Home.js"文件进行API调用并获取一些数据.我想将这些数据传递给"Dashboard.js"文件(组件)我研究过的所有示例中,它们都在同一个JS文件中显示了两个组件.

class Dashboard extends Component {
  constructor(props) {
    super(props);
    this.state  = {viz:{},filterData:{}};
  }
  var data1= ['1','2','3'];
  this.setState({data1: data1}, function () {
     console.log(this.state.data1);
  });

 }

//Sidebar

class Sidebar extends Component {

   constructor(props) {
     super(props);
     this.state  = {
       data: ['opt1','opt2']
     };
   }

  handleClick(e) {
    e.preventDefault();
    e.target.parentElement.classList.toggle('open');
    this.setState({data: this.state.data1}, function () {
      console.log(this.state.data);
    });
  }

  render() {

    const props = this.props;
    const handleClick = this.handleClick;

    return (
      <div className="sidebar">
        <nav className="sidebar-nav">
          <Nav>
            <li className="nav-item nav-dropdown">
              <p className="nav-link nav-dropdown-toggle" onClick={handleClick.bind(this)}>Global</p>
              <ul className="nav-dropdown-items">
              <li> Organization <br/>
               <select className="form-control">
                <option value="">Select </option>
                {this.state.data.map(function (option,key) {
                   return <option key={key}>{option}</option>;
                 })}
               </select>

Answer 1

如果必须将状态从仪表板传递到补充工具栏,则必须从仪表板的渲染功能渲染补充工具栏.在这里,您可以将仪表板的状态传递给补充工具栏.

代码段

class Dashboard extends Component {
...
...
  render(){
    return(
    <Sidebar data={this.state.data1}/>
    );
  }
}

如果您希望通过仪表板接收传递给补充工具栏的道具(data1)所做的更改,则需要提升状态.即,您必须将功能参考从仪表板传递到补充工具栏.在补充工具栏中,只要您希望将data1传递回Dashboard,就必须调用它.代码段.

class Dashboard extends Component {
  constructor(props){
    ...
    //following is not required if u are using => functions in ES6.
    this.onData1Changed = this.onData1Changed.bind(this);
  }
  ...
  ...
  onData1Changed(newData1){
    this.setState({data1 : newData1}, ()=>{
      console.log('Data 1 changed by Sidebar');
    })
  }

  render(){
    return(
    <Sidebar data={this.state.data1} onData1Changed={this.onData1Changed}/>
    );
  }
}

class Sidebar extends Component {
  ...
  //whenever data1 change needs to be sent to Dashboard
  //note: data1 is a variable available with the changed data
  this.props.onData1changed(data1);
}

参考文档:https://facebook.github.io/react/docs/lifting-state-up.html