React:如何监听子组件事件 [英] React: How to listen to child component events
问题描述
我有一个组件,假设它包含一个表单。该表单具有子组件,它们本质上是用于输出文本输入和选择菜单的UI小部件。
I have a component, let's say it contains a form. The form has child components which are essentially UI widgets for outputting text inputs and select menus.
选择菜单组件有点花哨,并使用onChange事件进行一些状态维护。
The select menu components are a bit fancy and do some state maintaining using the onChange event.
我的问题是;如何从父(表单)组件挂钩到选择菜单的onChange事件?我无法通过道具传递更改,因为我已经在select组件中指定了onChange并且我不想覆盖它。
My question is; how do I hook into the onChange event for a select menu from the parent (form) component? I can't pass onChange through props as I already have onChange specified inside the select component and I don't want to override it.
示例:
var Form = React.createClass({
handleSelectChange: function(){
// Do something when <Select /> changes
},
render: function () {
var selectMenuOptions = [
{label: 'Choose...', value: ''},
{label: 'First option', value: 'one'},
{label: 'Second option', value: 'two'}
];
return (
<form>
<Select name="selectMenu" id="selectMenu" options={selectMenuOptions} />
</form>
);
}
});
var Select = React.createClass({
getDefaultProps: function() {
return {
options: [],
className: "select"
};
},
getInitialState: function () {
return {
buttonText: 'Loading...',
defaultValue: null
};
},
handleChange: function (e) {
// Update buttonText state
},
render: function () {
return (
<div className={this.props.className}>
<div className="select__button">{this.state.buttonText}</div>
<select className="select__selector"
ref="select"
onChange={this.handleChange}>
{this.props.options.map(function(option, i){
return (<Option option={option} key={i} />);
})}
</select>
</div>
);
}
});
推荐答案
使用<选择onChange = {...} />
不会覆盖< select onChange = {...} />
里面的选择渲染
方法。 < Select />
组件及其呈现的< select />
组件具有完全不同的组合道具
。
Using <Select onChange={...} />
won't override the <select onChange={...} />
inside Select's render
method. The <Select/>
component and the <select/>
component it renders have completely different sets of props
.
我认为,做你想做的最简单的方法就是让你的选择 handleChange
方法调用 this.props.onChange
。你可以传递相同的 e
参数 handleChange
收到:
The simplest way to do what you want, I think, is to have your Select's handleChange
method call this.props.onChange
. You can just pass it the same e
argument handleChange
receives:
var Form = React.createClass({
handleSelectChange: function(){
// Do something when <Select /> changes
},
render: function () {
// ...
return (
<form>
<Select name="selectMenu"
id="selectMenu"
options={selectMenuOptions}
onChange={this.handleSelectChange} />
</form>
);
}
});
var Select = React.createClass({
// ...
handleChange: function (e) {
if (this.props.onChange) {
this.props.onChange(e);
}
// Update buttonText state
},
render: function () {
return (
<div className={this.props.className}>
<div className="select__button">{this.state.buttonText}</div>
<select className="select__selector"
ref="select"
onChange={this.handleChange}>
{this.props.options.map(function(option, i){
return (<Option option={option} key={i} />);
})}
</select>
</div>
);
}
});
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