[已解决]解决方案是:1)'extends React.Component'不再自动绑定。 2)'filterText'变量需要被发送'handleUserInput(filterText)'...
感谢你所做的一切!!
美好的一天。此代码正在处理“React.createClass”,现在我正在尝试将其更改为“extends React.Component”。目的是通过在输入中输入值来对元素进行排序。
代码:
TheSecondComponent...
constructor(props){
super(props);
}
handleChange() {
this.props.onUserInput(
this.refs.filterTextInput.value
);
}
render() {
return (
<form className='Center'>
<input
type="text"
value={this.props.filterText}
ref="filterTextInput"
onChange={this.handleChange}
/>
</form>
);
}
TheFirstComponent...
constructor(){
super();
this.state={'filterText': ''} // If to use setState here than I have one
more error, added in the end of the question
this.handleUserInput=this.handleUserInput.bind(this);
}
getInitialState() {
return {
filterText: ''
};
}
handleUserInput(filterText) {
//this.setState({filterText: filterText});
this.state = {filterText: filterText};
}
render() {
return (
<div>
<div>
<SearchBar
filterText={this.state.filterText}
onUserInput={this.handleUserInput}
/>
<CreateButtons
source={this.props.citys}
filterText={this.state.filterText}
/>
</div>
</div>
);
}
“React.createClass”的WORKING代码:
TheFirstComponent...
({
handleChange: function() {
this.props.onUserInput(
this.refs.filterTextInput.value
);
},
render: function() {
return (
<form className='Center'>
<input
type="text"
value={this.props.filterText}
ref="filterTextInput"
onChange={this.handleChange}
/>
</form>
);
}
});
TheSecondComponent...
({
getInitialState: function() {
return {
filterText: ''
};
},
handleUserInput: function(filterText) {
this.setState({
filterText: filterText
});
},
render: function() {cl(this);
return (
<div>
<div className='SLFirst'>
<SearchBar
filterText={this.state.filterText}
onUserInput={this.handleUserInput}
/>
<CreateButtons
source={this.props.citys}
filterText={this.state.filterText}
/>
</div>
</div>
);
}
});
有错误:我试图在“输入”中输入任何文本,但它不会写入值。我的意思是,我正在打字,但没有任何改变。是因为
this.state={'filterText': ''}
?
我该怎么玩呢?如果不设置''但'sometext'那么这个'sometext'将是不可替换的。
正如我发现“setState”不再有效。如果要使用'setState',那么请使用更多:
TypeError: Cannot read property 'filterText' of null
40 | <div>
41 | <div className='SLFirst'>
42 | <SearchBar
> 43 | filterText={this.state.filterText}
44 | onUserInput={this.handleUserInput}
45 | />
46 | <CreateButtons
你没有绑定handleChange()。要解决此问题,您必须绑定在构造函数()中使用“this”的方法。请尝试以下代码
constructor(props){
super(props);
this.handleChange = this.handleChange.bind(this)
}
handleChange() {
this.props.onUserInput(
this.refs.filterTextInput.value
);
}
render() {
return (
<form className='Center'>
<input
type="text"
value={this.props.filterText}
ref="filterTextInput"
onChange={this.handleChange}
/>
</form>
);
}
this.state = {...}不会触发重新渲染,更新你的状态使用setState函数
setState可以是一个对象
//the following will update the filterText property on the state object
this.setState({filterText: ''})
或功能
this.setState(function(state){
state.filterText = '';
// make sure you return state
return state
})
确保在构造函数中初始化状态对象,如下所示
constructor(props){
super(props);
this.state = {
filterText: 'initiale value'
}
}