廢話不多說,直接上代碼。
代碼如下:
1、封裝一個公共檔案createContext.js
在src/utils檔案夾下建立一個createContext.js檔案,代碼如下:
// createContext.js檔案
import { createContext } from "react";
const myContext = createContext(null);
export default myContext;
2、在父元件中使用
import React, { useState} from "react";
import Count from './count'
import myContext from '@/utils/createContext'
function App() {
const [count, setCount] = useState(0);
return (
<div>
<h3>Father</h3>
<p>You clicked {count} times</p>
<button onClick={() => { setCount(count + 1) }}>
click me
</button>
<myContext.Provider value={count}>
<Count />
</myContext.Provider>
</div>
);
}
export default App;
3、建立子元件count.tsx:
import React, { useContext} from 'react';
import myContext from '@/utils/createContext'
function Count() {
const count = useContext(myContext); // 得到父元件傳的值
return (
<div>
<h3>我是子元件</h3>
<p>這是父元件傳過來的值:{count}</p>
</div>
)
}
export default Count;