node.js - 如何在 React 中成功提交后清除输入字段,使用 useEffect 功能组件
问题描述
我正在开发一个 Mern-stack 应用程序,但在成功发布请求后我无法清除输入字段。我正在使用带有 useEffect 的基于函数的组件。
我尝试了我在 Stack Overflow 上获得的示例,但它仍然不起作用。提交成功后,输入仍然留在输入字段中。我该如何澄清?
提交后我试过setCommentData([])
了,但是没有用。
这是我的组件
export default function EventAndComments(props) {
const EventComment = (props) => (
<CardContent>
<Typography variant="body2" color="textSecondary" component="p">
{props.comment.name}
</Typography>
<Typography variant="body2" color="textSecondary" component="p">
{props.comment.description}
</Typography>
</CardContent>
);
const theme = useTheme();
const [events, setEventData] = useState([]);
const [comments, setCommentData] = useState([]);
const useStyles = makeStyles((theme) => ({
root: {
maxWidth: 550,
},
media: {
height: 0,
paddingTop: "86%", // 16:9
display: "flex",
flexDirection: "column",
alignItems: "center",
},
expand: {
transform: "rotate(0deg)",
marginLeft: "auto",
transition: theme.transitions.create("transform", {
duration: theme.transitions.duration.shortest,
}),
},
expandOpen: {
transform: "rotate(180deg)",
},
avatar: {
backgroundColor: red[500],
},
}));
const classes = useStyles();
const [expanded, setExpanded] = React.useState(false);
const handleExpandClick = () => {
setExpanded(!expanded);
};
useEffect(() => {
axios
.get(
"http://localhost:9000/events/" +
props.match.params.id +
"/eventcomments"
)
.then((response) => {
setEventData(response.data);
})
.catch(function (error) {
console.log(error);
});
}, []);
const onPageLoad = () => {
axios
.get(
"http://localhost:9000/events/" +
props.match.params.id +
"/eventcomments"
)
.then((response) => {
setCommentData(response.data.eventcomments);
})
.catch(function (error) {
console.log(error);
});
};
useEffect(() => {
onPageLoad();
}, []);
const nowIso = new Date();
const getTitle = (startDateTs, endDateTs) => {
const now = Date.parse(nowIso);
if (endDateTs <= now) {
return "Started:" + " " + moment(startDateTs).format("LLLL");
}
if (startDateTs < now && endDateTs > now) {
return "Live:" + " " + moment(startDateTs).format("LLLL");
}
return "Starting:" + " " + moment(startDateTs).format("LLLL");
};
const getEnded = (startDateTs, endDateTs) => {
const now = Date.parse(nowIso);
if (endDateTs <= now) {
return "Ended:" + " " + moment(startDateTs).format("LLLL");
}
if (startDateTs < now && endDateTs > now) {
return "Will End:" + " " + moment(startDateTs).format("LLLL");
}
return "Ends:" + " " + moment(startDateTs).format("LLLL");
};
const [eventDescription, setEventComment] = React.useState("");
const [name, setName] = React.useState("");
const handleChange = (parameter) => (event) => {
if (parameter === "name") {
setName(event.target.value);
}
if (parameter === "description") {
setEventComment(event.target.value);
}
};
const onSubmit = useCallback(
(e) => {
e.preventDefault();
axios
.post(
"http://localhost:9000/events/" +
props.match.params.id +
"/eventcomment",
{ name: name, description: eventDescription }
)
.then(function (response) {
onPageLoad();
})
.catch(function (error) {
console.log(error);
});
},
[props.match.params.id, name, eventDescription]
);
let eventCommentList = comments.map((comment, k) => (
<EventComment comment={comment} key={k} />
));
return (
<Grid
container
spacing={0}
direction="column"
alignItems="center"
justify="center"
style={{ minHeight: "100vh" }}
>
<Card className={classes.root}>
<h3
style={{
background: " #800000",
color: "white",
textAlign: "center",
}}
className={classes.cardheader}
>
{events.title}
</h3>
<CardHeader
avatar={
<Avatar aria-label="recipe" className={classes.avatar}>
CB
</Avatar>
}
action={
<IconButton aria-label="settings">
<MoreVertIcon />
</IconButton>
}
title={getTitle(
Date.parse(events.startingDate),
Date.parse(events.closingDate)
)}
subheader={getEnded(
Date.parse(events.startingDate),
Date.parse(events.closingDate)
)}
style={{ background: "#DCDCDC" }}
/>
<CardMedia
className={classes.media}
image={events.eventImage}
title="Paella dish"
/>
<CardContent>
<Typography variant="body2" color="textSecondary" component="p">
{events.description}
</Typography>
</CardContent>
</Card>
<form
className={classes.root}
noValidate
autoComplete="off"
onSubmit={onSubmit}
>
<FormControl>
<InputLabel htmlFor="component-simple">Name</InputLabel>
<Input
id="component-simple"
value={name}
onChange={handleChange("name")}
label="Name"
/>
</FormControl>
<FormControl variant="outlined">
<InputLabel htmlFor="component-outlined">Description</InputLabel>
<OutlinedInput
id="component-outlined"
value={eventDescription}
onChange={handleChange("description")}
label="Description"
/>
</FormControl>
<Button type="submit" fullWidth variant="contained" color="primary">
Create Comment
</Button>
</form>
<CardContent>{eventCommentList}</CardContent>
</Grid>
);
}
}
我在上面添加了所有代码。
解决方案
在您的onSubmit
函数中,调用setName("")
并setEventComment("")
清除这些值。
另外,为了遵循约定,我将重命名setEventComment
为,setEventDescription
因为状态变量被命名为eventDescription
not eventComment
。
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