当我将子组件的状态发送到其父组件时，React 将旧状态发送到父组件。

我想在每次单击 ListItem 时发送更新的状态，该状态正常工作并调用函数 handleItemClick。

但是当我打电话时sendStateToParent。它正在过去它的旧状态。假设我点击了ITEM1，它正在发送空数组[]。接下来我点击了ITEM2，它正在发送数组[ITEM1]。

在这里，我实际上是在创建一个多选下拉列表。它也可以作为基于它获得的props的单一选择。

import React from 'react';
import ListItemComponent from './ListItem.jsx';
import DropDownButtonComponent from './DropDownButton.jsx';
import DropDownStyle from '../../../../css/sass/drop-down.scss';

module.exports = React.createClass({
  handleClick: function () {
    this.setState({open: !this.state.open});
  },
  getInitialState: function () {
    return {
      open: false,
      //listItems: this.props.listItems,
      selectedItems:[],
      title: this.props.dropdownTitle
    }
  },
  handleItemClick: function (item) {
    var selectedItems = [];
    if(this.props.multiple == true){
      selectedItems = this.state.selectedItems;
      if(selectedItems.indexOf(item)==-1){
        selectedItems.push(item);
      }else{
        selectedItems.splice(selectedItems.indexOf(item),1)
      }
      this.setState({
        title: this.state.selectedItems.length+" selected",
        selectedItems: selectedItems
      });
    } else{
      selectedItems = [];
      selectedItems.push(item);
      this.setState({
        title: item,
        selectedItems: selectedItems,
        open: false
      });
    }
    this.sendStateToParent();
  },
  sendStateToParent: function(){
    this.props.ifListChanged(this);
  },
  handleTextChange: function (event) {
    var filteredItems = [];
    this.props.listItems.map(function(item){
      if(item.toLowerCase().search(event.target.value.toLowerCase()) != -1){
        filteredItems.push(item);
      }
    },this);
    this.setState({
      listItems: filteredItems
    });
  },
  clearSelected: function(){
    this.setState({
      title: this.props.dropdownTitle,
      selectedItems: [],
    });
  },
  render: function () {
    var index = 0;
    var list=[];
    if (this.state.listItems != undefined) {
      list = this.state.listItems.map(function (item) {
        return (
          <ListItemComponent
            key={index++}
            item={item}
            whenItemClicked={this.handleItemClick}
            className={this.state.selectedItems.indexOf(item) != -1 ? "active" : ""}
          />);
      }.bind(this));
    } else {
      list = this.props.listItems.map(function (item) {
        return (
          <ListItemComponent
            key={index++}
            item={item}
            whenItemClicked={this.handleItemClick}
            className={this.state.selectedItems.indexOf(item) != -1 ? "active" : ""}
          />);
      }.bind(this));
    }

    return <div className="btn-group bootstrap-select form-control">
      <DropDownButtonComponent
        whenClicked={this.handleClick}
        title={this.state.title}
      />
      <ul className={"dropdown-menu inner dropdown-menu " + (this.state.open ? "show" : "") }>
        {this.props.search? <li><input type="text" style={{margin:"auto", maxWidth:"96%"}} onChange={this.handleTextChange} placeholder="Search"/></li> :""}
        <li className="disabled"><a>Select from below list {this.props.multiple ? <i title="clear all" style={{fontSize:"15px"}} onClick={this.clearSelected} className="text-danger fa fa-ban pull-right"></i>: ""}</a></li>
        {list}
      </ul>
    </div>
  }
});

提前致谢