我正在尝试删除一个项目，但每次单击按钮时，它都会返回错误"dispatch is not a function"

Question

我正在处理CRUD应用程序，我通过API获取数据，一切都在工作，除了当我试图删除一个项目时。如果我点击按钮，它会返回一个错误：

调度不是一个函数。

ADD和UPDATE操作运行良好，而不是DELETE。如果你想查看项目并给我反馈，回购是可在Github上获得。

const Return = (props, {dispatch}) =>{
const initialFormState = {
id:props.id, studentID: '', booknum: props.booknum,
rented: '', exist: ''
}
const[data, setData]=useState(initialFormState)
const [modal, setModal] = useState(false);
const handleFormState = e=>{
const {name, value} = e.target
setData({...data, [name]: value})
}
const toggle = () => setModal(!modal);

const studentRented = (studentID, booknum) =>{
let id = []
let num = props.getRented.length
props.getRented.filter((key) =>{
return ((parseInt(key.studentID) === parseInt(studentID)) && (key.booknum == booknum))?
id.push(key.id) :  num = num -1
}) 
return id 
}
const studentExist = (studentID)=>{
let num = props.students.length
props.students.filter((student) =>{
return (parseInt(student.studentID) === parseInt(studentID))?
null  : num = num - 1
}) 
return num 
}
const onSubmit=(e)=>{
e.preventDefault();
if(!data.booknum || !data.studentID){
setState(() => ({ error: 'One of the field is empty' }));
}else{
const info ={
studentID: data.studentID,
booknum: data.booknum
}
let ids = studentRented(data.studentID, data.booknum)[0]  
try{
// this dispatch return an error "dispatch nit a function 
(parseInt(studentExist(info.studentID)) === 0) ?
setState(() =>({exist: `This student does not exist`})):
(studentRented(info.studentID, info.booknum).length === 1)  ?
dispatch(removeRent({ids})):
setState(() =>({rented: `This student did not checkout this book`}))
}catch(err){
console.log({err: err});
}                         
}    
}  
//
return(
<div>
<small color="danger" onClick={toggle}>RETURN</small>
<Modal isOpen={modal} toggle={toggle} >
<ModalHeader toggle={toggle}>Modal title.</ModalHeader>
<ModalBody>
<Form onSubmit={onSubmit}>              
<FormGroup>
{data.rented && <p className='error text-danger'>Rented:{data.rented}</p>}   
{data.exist && <p className='error text-danger'>Exist:{data.exist}</p>}
<Label for="title">Student ID</Label>
<Input type="number"name="studentID"id="b" value={data.studentID} onChange={handleFormState} />
</FormGroup>
<FormGroup>
<Label for="title">ISBN</Label>
<Input type="text" name="isbn" id="isbn"palceholder="add ISBN" value={data.booknum}
onChange={handleFormState}/>
</FormGroup>
<FormGroup>
<Button color="dark" style={{marginTop: '2rem'}} block>Submit</Button>
</FormGroup>
</Form>
</ModalBody>
</Modal>
</div>
);
};
const mapStateToProps = (state) =>{
return{
getRented: state.rentReducer,
students: state.studentReducer
}
}
export default connect(mapStateToProps, {getRents, getStudents})(Return);

Answer 1

React功能组件是函数，但它们只接收一个参数，一个props对象。react-redux的connectHOC注入dispatch道具以及将state和dispatch映射到props。

访问props对象

const Return = (props) => {
...
props.dispatch(...some action object);
...

或函数签名中的析构函数

const Return = ({ booknum, dispatch, getRented, id, <... other props> }) => {
...
dispatch(...some action object);
...