如何從React中的另一個組件調用函數
[英]how to call a function from another component in react
問題描述
我在“添加新候選”按鈕的單擊上附加了一個文本框，並且我還想在“保存”按鈕的單擊上調用驗證NewCandidate組件的功能。我嘗試使用以下代碼，但是如果有人知道解決方案，則會拋出錯誤，請回答................................................... ................................................... .....................................
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>Hello React!</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.7/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.7/react-dom.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.0-alpha1/JSXTransformer.js"></script>
<script src="https://www.gstatic.com/firebasejs/3.9.0/firebase.js"></script>
</head>
<body>
<div id="root"></div>
<script type="text/jsx">
class NewCandidate extends React.Component{
validate(){
alert()
}
render(){
return(
<table>
<tr>
<th colSpan="2">Candidate details</th>
</tr>
<tr>
<th>Name</th><td><input type="text" ref="candName" /></td>
</tr>
</table>
)
}
}
var CandidateList = [<NewCandidate />];
class Interview extends React.Component{
constructor(props){
super();
this.state={candidates:props.candidates}
}
updateCandidateList(newCandidate){
var updatedCandidates=this.state.candidates;
updatedCandidates.push(newCandidate);
this.setState({candidates: updatedCandidates})
}
render(){
return(
<div>
<Candidate candidates={this.state.candidates} />
<AddNewCandidate candidateList={this.updateCandidateList.bind(this)} />
</div>
)
}
}
class AddNewCandidate extends React.Component{
constructor(){
super()
}
addNewCandidate(e){
e.preventDefault();
this.props.candidateList(<NewCandidate />)
}
render(){
return(
<form>
<button onClick={this.addNewCandidate.bind(this)}>Add New Candidate</button>
<button type="button" onClick={NewCandidate.validate.bind(this)}>Save</button>
</form>
)
}
}
class Candidate extends React.Component{
constructor(props){
super(props);
}
render(){
var items=this.props.candidates.map((item)=>{
return (<div>{item}</div>)
});
return(
<div>
{items}
</div>
)
}
}
ReactDOM.render(<Interview candidates={CandidateList}/>,document.getElementById("root"));
</script>
</body>
</html>
2 個解決方案
解決方案1
0 2017-10-21 14:41:09
這是一個例子。 App的主要組件充當所有相關信息和操作的容器。 然后，我們使用用於呈現數據的子組件，這些子組件將使用從容器傳遞來執行操作的方法。
class NewCandidate extends React.Component { state = { name: "" }; handleChange = evt => this.setState({ name: evt.target.value }); addCandidate = () => { const { name } = this.state; if (name === "") { return console.warn("input is empty"); } return this.setState({ name: '', }, () => this.props.add(name)); }; render() { if (this.props.display) { return ( <div> <label>Name</label> <input type="text" value={this.state.name} onChange={this.handleChange} /> <button onClick={this.addCandidate}>Add Candidate</button> </div> ); } return null; } } const Candidate = ({ candidate }) => <div>{candidate.name}</div>; class App extends React.Component { state = { showNewCandidateForm: false, candidates: [ { id: 1, name: "Jeff" }, { id: 2, name: "Andrew" }, { id: 3, name: "Jess" } ] }; addCandidate = name => { alert('validation here'); const { candidates } = this.state; this.setState({ showNewCandidateForm: false, candidates: [ ...candidates, { id: candidates[candidates.length - 1].id + 1, name, } ] }); }; showNewCandidateForm = () => this.setState({ showNewCandidateForm: true }); hideNewCandidateForm = () => this.setState({ showNewCandidateForm: false }); render() { return ( <div> <NewCandidate display={this.state.showNewCandidateForm} hide={this.hideNewCandidateForm} add={this.addCandidate} /> {this.state.candidates.map(candidate => { return <Candidate key={candidate.id} candidate={candidate} />; })} <button onClick={this.showNewCandidateForm}>New Candidate</button> </div> ); } } ReactDOM.render(<App />, document.getElementById("root"));
<div id="root"></div> <script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
解決方案2
0 已采納 2017-10-21 15:44:42
請檢查以下工作片段。
<!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <title>Hello React!</title> <script src="https://unpkg.com/react@15/dist/react.js"></script> <script src="https://unpkg.com/react-dom@15/dist/react-dom.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.23/browser.min.js"></script> <script src="https://www.gstatic.com/firebasejs/3.9.0/firebase.js"></script> </head> <body> <div id="root"></div> <script type="text/babel"> class NewCandidate extends React.Component { constructor(props) { super(props); this.handleChange = this.handleChange.bind(this); } handleChange(e){ e.preventDefault(); this.props.handleCandidateChange(e.target.value, this.props.indexVal); } render(){ return( <div> <table> <tbody> <tr> <th colSpan="2">Candidate details</th> </tr> <tr> <th>Name</th><td><input type="text" onChange={this.handleChange}/></td> </tr> </tbody> </table> </div> ) } } class Interview extends React.Component { constructor(props){ super(props); this.state = { candidates: [], values: [] } this.addNewCandidate = this.addNewCandidate.bind(this); this.handleSave = this.handleSave.bind(this); this.handleCandidateChange = this.handleCandidateChange.bind(this); } handleCandidateChange(value, index) { const newValues = [].concat(this.state.values); newValues[index] = value; this.setState({values: newValues}); } handleSave(e) { e.preventDefault(); this.state.values.forEach((val, index) => { alert(`Validate ${index+1} value`); }) } addNewCandidate(e) { e.preventDefault(); const candidateList = [].concat(this.state.candidates); candidateList.push(<div key={`candidate-${candidateList.length}`}><NewCandidate indexVal={candidateList.length} handleCandidateChange={this.handleCandidateChange}/></div>) this.setState({candidates: candidateList}); } render() { return ( <div> {this.state.candidates} <button type="button" onClick={this.addNewCandidate}>Add New Candidate</button> <button type="button" onClick={this.handleSave}>Save</button> </div> ) } } // render Interview component ReactDOM.render(<Interview />,document.getElementById("root")); </script> </body> </html>
如何從其他組件調用/執行方法/函數
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