action.js
import axios from 'axios';
import { EVENT_ADD_FAIL, EVENT_ADD_REQUEST, EVENT_ADD_SUCCESS } from '../constraints/eventConstraint';
const addEvent = (event) => async (dispatch) => {
dispatch({ type: EVENT_ADD_REQUEST, payload: event });
try {
const { data } = await axios.post(`http://localhost:4000/event`, event);
dispatch({ type: EVENT_ADD_SUCCESS, payload:data });
}
catch (error) {
dispatch({ type: EVENT_ADD_FAIL, payload:error.message });
};
};
export { addEvent };
constraint.js
export const EVENT_ADD_REQUEST = 'EVENT_ADD_REQUEST';
export const EVENT_ADD_SUCCESS = 'EVENT_ADD_SUCCESS';
export const EVENT_ADD_FAIL = 'EVENT_ADD_FAIL';
reducer.js
import {EVENT_ADD_FAIL, EVENT_ADD_REQUEST, EVENT_ADD_SUCCESS } from "../constraints/eventConstraint";
function eventAddReducer(state = {}, action) {
switch(action.type) {
case EVENT_ADD_REQUEST:
return { loading: true };
case EVENT_ADD_SUCCESS:
return { loading: false, event: action.payload, success:true };
case EVENT_ADD_FAIL:
return { loading: false, error: action.payload, success:false };
default:
return state
};
};
export { eventAddReducer }
store.js
import { createStore, combineReducers, applyMiddleware, compose } from 'redux';
import thunk from 'redux-thunk';
import { eventAddReducer } from './reducers/eventReducer';
const initialState = {};
const reducer = combineReducers({
addEvent: eventAddReducer
});
const store = createStore(reducer, initialState, compose(applyMiddleware(thunk)));
export default store
event.js
import React, { useState } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { Link, useHistory } from 'react-router-dom';
import { addEvent } from '../actions/eventAction';
const AddEvent = () => {
const history = useHistory();
const [event, setEvent] = useState();
const addNewEvent = useSelector(state => state.addEvent);
console.log(addNewEvent)
const dispatch = useDispatch();
const handleChange = e => {
setEvent({ ...event,[e.target.name]:e.target.value})
};
const submitHandler = async (e) => {
e.preventDefault();
await dispatch(addEvent(event));
};
// if(addNewEvent.success === true) {
// history.push('/')
// }; ===========>>>>>>>>>>> It works at first but after submission first time next time it automatically redirects to '/' because react-redux holds state
return (
<>
<form onSubmit = { submitHandler } >
<div className="form-group">
<label htmlFor="name">Name:</label>
<input type="text" className="form-control" id="name" name="name" onChange={e => handleChange(e)} />
</div>
<div className="form-group">
<label htmlFor="description">Description:</label>
<input type="text" className="form-control" id="description" name="description" onChange={e => handleChange(e)} />
</div>
<div className="form-group">
<label htmlFor="price">Price:</label>
<input type="text" className="form-control" id="price" name="price" onChange={e => handleChange(e)} />
</div>
<Link to='/'> <button type="button" className="btn btn-success"> Back </button> </Link>
<button type="submit" className="btn btn-success float-right"> Add Event </button>
</form>
</>
)
};
export default AddEvent
一切正常，但我希望成功提交表单后需要将其重定向到某个页面。没有react-redux很简单，我们可以在提交表单后直接重定向，但是我正在尝试学习redux，对redux并不了解。我尝试在reducer中使用success = true，但它在第一次使用时有效，但是当我尝试打开链接时，由于redux保持状态，所以它会自动重定向到主页，因为react-redux持有成功= true。任何帮助将不胜感激
答案 0 :(得分：0)
首先：请确保您为每个操作重置success：
function eventAddReducer(state = {}, action) {
switch(action.type) {
case EVENT_ADD_REQUEST:
return {
loading: true,
success: null // <-- Look at this
};
/** ... */
};
};
第二步：将success存储变量连接到您的组件，并在componentDidupdate事件中检查它，例如：
import { connect } from 'react-redux';
class AddEvent extends React.Component {
componentDidUpdate(prevProps) {
const {success} = this.props;
const {succcess: prevSuccess} = prevProps;
if (success && success !== prevSuccess) {
/** Redirect here */
}
}
/** .... */
}
const mapStateToProps = ({ addEvent: { success } }) => ({
success
});
export default connect(mapStateToProps)(AddEvent);
使用挂钩
const AddEvent = ({ success }) => {
useEffect(() => {
if (success) {
/** Redirect here */
}
}, [success]); // <-- This will make sure that the effect only runs when success variable has changed
};
const mapStateToProps = ({ addEvent: { success } }) => ({
success
});
export default connect(mapStateToProps)(AddEvent);
答案 1 :(得分：0)
我知道这不是最理想的解决方案，但是如何创建一个操作来重置成功并将其分派到useEffect内呢？
类似这样的东西：
减速器
import {EVENT_ADD_FAIL, EVENT_ADD_REQUEST, EVENT_ADD_SUCCESS } from "../constraints/eventConstraint";
function eventAddReducer(state = {}, action) {
switch(action.type) {
case EVENT_ADD_REQUEST:
return { loading: true };
case EVENT_ADD_SUCCESS:
return { loading: false, event: action.payload, success:true };
case EVENT_ADD_FAIL:
return { loading: false, error: action.payload, success:false };
case RESET:
return {
...state,
loading: false,
success:false
} // This will reset everything including success
default:
return state
};
};
export { eventAddReducer }
，然后在event.js文件中调用一个将调度RESET的操作。确保将其放在有用的效果之内。
import React, { useState } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { Link, useHistory } from 'react-router-dom';
import { addEvent } from '../actions/eventAction';
const AddEvent = () => {
const history = useHistory();
const [event, setEvent] = useState();
const addNewEvent = useSelector(state => state.addEvent);
console.log(addNewEvent)
const dispatch = useDispatch();
React.useEffect(() =>{
myResetAction()
}, [])
const handleChange = e => {
setEvent({ ...event,[e.target.name]:e.target.value})
};
const submitHandler = async (e) => {
e.preventDefault();
await dispatch(addEvent(event));
};
// if(addNewEvent.success === true) {
// history.push('/')
// }; ===========>>>>>>>>>>> It works at first but after submission first time next time it automatically redirects to '/' because react-redux holds state
return (
<>
<form onSubmit = { submitHandler } >
<div className="form-group">
<label htmlFor="name">Name:</label>
<input type="text" className="form-control" id="name" name="name" onChange={e => handleChange(e)} />
</div>
<div className="form-group">
<label htmlFor="description">Description:</label>
<input type="text" className="form-control" id="description" name="description" onChange={e => handleChange(e)} />
</div>
<div className="form-group">
<label htmlFor="price">Price:</label>
<input type="text" className="form-control" id="price" name="price" onChange={e => handleChange(e)} />
</div>
<Link to='/'> <button type="button" className="btn btn-success"> Back </button> </Link>
<button type="submit" className="btn btn-success float-right"> Add Event </button>
</form>
</>
)
)}
这样做会有所帮助。