如何在React中轻松设置兄弟组件的状态？

Question

我有一个可点击列表组件的开头,它将用于驱动一个select元素.正如你可以从下面看,onClick的ListItem,我路过一个子元素的状态(ListItem在这种情况下)父母(SelectableList及CustomSelect组件).这工作正常.但是,我还想做的是更改兄弟组件(其他ListItems)的状态,以便在单击其中一个ListItem时切换其选定状态.

目前,我只是使用document.querySelectorAll('ul.cs-select li)抓取元素并将类更改为与所单击的索引不匹配时选择的ListItem.这在某种程度上有效.但是,在几次单击之后,组件的状态尚未由React更新(仅由客户端JS),并且事情开始崩溃.我想要做的是更改this.state.isSelected兄弟列表项,并使用此状态刷新SelectableList组件.任何人都可以提供一个比我下面写的更好的替代品吗？

var React = require('react');
var SelectBox = require('./select-box');

var ListItem = React.createClass({
    getInitialState: function() {
        return {
            isSelected: false
        };
    },

    toggleSelected: function () {
        if (this.state.isSelected == true) {
            this.setState({
                isSelected: false
            })
        } else {
            this.setState({
                isSelected: true
            })
        }
    },

    handleClick: function(listItem) {
        this.toggleSelected();
        this.props.onListItemChange(listItem.props.value);

        var unboundForEach = Array.prototype.forEach,
            forEach = Function.prototype.call.bind(unboundForEach);

        forEach(document.querySelectorAll('ul.cs-select li'), function (el) {

            // below is trying to 
            // make sure that when a user clicks on a list
            // item in the SelectableList, then all the *other*
            // list items get class="selected" removed.
            // this works for the first time that you move through the 
            // list clicking the other items, but then, on the second
            // pass through, starts to fail, requiring *two clicks* before the
            // list item is selected again.
            // maybe there's a better more "reactive" method of doing this?

            if (el.dataset.index != listItem.props.index && el.classList.contains('selected') ) {
                el.classList.remove('selected');
            }
        });
    },

    render: function() {
        return (
            <li ref={"listSel"+this.props.key}
                data-value={this.props.value}
                data-index={this.props.index}
                className={this.state.isSelected == true ? 'selected' : '' } 
                onClick={this.handleClick.bind(null, this)}>
                {this.props.content}
            </li>
        );
    }
});

var SelectableList = React.createClass({

    render: function() {

        var listItems = this.props.options.map(function(opt, index) {
            return <ListItem key={index} index={index} 
                        value={opt.value} content={opt.label}
                        onListItemChange={this.props.onListItemChange.bind(null, index)} />;
        }, this);

        return <ul className="cs-select">{ listItems }</ul>;
    }

})

var CustomSelect = React.createClass({

    getInitialState: function () {
        return {
            selectedOption: ''
        }
    },

    handleListItemChange: function(listIndex, listItem) {
        this.setState({
            selectedOption: listItem.props.value
        })
    },

    render: function () {

        var options = [{value:"One", label: "One"},{value:"Two", label: "Two"},{value:"Three", label: "Three"}];

        return (
            <div className="group">
                <div className="cs-select">
                    <SelectableList options={options} 
                        onListItemChange={this.handleListItemChange} />
                    <SelectBox className="cs-select" 
                        initialValue={this.state.selectedOption} 
                        fieldName="custom-select" options={options}/>
                </div>
            </div>
        )
    } 
})

module.exports = CustomSelect;

Answer 1

父组件应该将回调传递给子组件,并且每个子组件在其状态更改时将触发该回调.您实际上可以将父级中的所有状态保存为单点,并将"选定"值作为道具传递给每个子项.

在这种情况下,孩子可能看起来像这样:

var Child = React.createClass({
    onToggle: function() {
        this.props.onToggle(this.props.id, !this.props.selected);
    },

    render: function() {
        return <button onClick={this.onToggle}>Toggle {this.props.label} - {this.props.selected ? 'Selected!' : ''}!</button>;
    }
});

它没有状态,它只是onToggle在点击时触发回调.父母看起来像这样:

var Parent = React.createClass({
    getInitialState: function() {
        return {
            selections: []
        };
    },
    onChildToggle: function(id, selected) {
        var selections = this.state.selections;

        selections[id] = selected;

        this.setState({
            selections: selections
        });
    },

    buildChildren: function(dataItem) {
        return <Child
            id={dataItem.id}
            label={dataItem.label}
            selected={this.state.selections[dataItem.id]}
            onToggle={this.onChildToggle} />
    },

    render: function() {
        return <div>{this.props.data.map(this.buildChildren)}</div>
    }
});

它包含状态中的一系列选择,当它处理来自子进程的回调时,它setState通过将其状态向下传递selected给每个子进程来重新呈现子进程.

你可以在这里看到一个有效的例子:

https://jsfiddle.net/fth25erj/