我搜索了答案,但没有找到任何解决方法,所以我在这里提问。我有一个消费者,可以更新上下文,并且另一个消费者应该显示上下文。我正在使用带有TypeScript(16.3)的React。
上下文(AppContext.tsx):
export interface AppContext {
jsonTransactions: WithdrawTransactionsElement | null;
setJsonTran(jsonTransactions: WithdrawTransactionsElement | null): void;
}
export const appContextInitialState : AppContext = {
jsonTransactions: null,
setJsonTran : (data: WithdrawTransactionsElement) => {
return appContextInitialState.jsonTransactions = data;
}
};
export const AppContext = React.createContext(appContextInitialState);
制作人(App.tsx):
interface Props {}
class App extends React.Component<Props, AppContext> {
state: AppContext = appContextInitialState;
constructor(props : Props) {
super(props);
}
render() {
return (
<AppContext.Provider value={this.state}>
<div className="App">
<header className="App-header">
<SubmitTransactionFile/>
<WithdrawTransactionsTable />
</header>
</div>
</AppContext.Provider>
);
}
}
export default App;
更新上下文消费者(SubmitTransactionFile.tsx)
class SubmitTransactionFile extends React.Component {
private fileLoadedEvent(file: React.ChangeEvent<HTMLInputElement>, context: AppContext): void{
let files = file.target.files;
let reader = new FileReader();
if (files && files[0]) {
reader.readAsText(files[0]);
reader.onload = (json) => {
if (json && json.target) {
// @ts-ignore -> this is because result field is not recognized by typescript compiler
context.setJsonTran(JSON.parse(json.target.result))
}
}
}
}
render() {
return (
<AppContext.Consumer>
{ context =>
<div className="SubmitTransactionFile">
<label>Select Transaction File</label><br />
<input type="file" id="file" onChange={(file) =>
this.fileLoadedEvent(file, context)} />
<p>{context.jsonTransactions}</p>
</div>
}
</AppContext.Consumer>
)
}
}
export default SubmitTransactionFile;
最后是显示消费者(WithdrawTransactionsTable.tsx):
class WithdrawTransactionsTable extends React.Component {
render() {
return (
<AppContext.Consumer>
{ context =>
<div>
<label>{context.jsonTransactions}</label>
</div>
}
</AppContext.Consumer>
)
}
}
export default WithdrawTransactionsTable;
我了解的是在调用fileLoadedEvent
函数后,context.setJsonTran
应该重新渲染其他相关组件,并且WithdrawTransactionsTable
组件也应该重新渲染,但实际上并没有。
我做错了什么?