如何在 Material UI (React JS) 中根据需要制作“选择"组件
除非有选择的选项,否则我想用红色显示错误.有没有办法做到这一点.
I want to display like an error with red color unless there is a selected option. Is there any way to do it.
推荐答案
要使用 Material UI 设置必填的 Select 字段,您可以这样做:
For setting a required Select field with Material UI, you can do:
class SimpleSelect extends React.PureComponent {
state = {
selected: null,
hasError: false
}
handleChange(value) {
this.setState({ selected: value });
}
handleClick() {
this.setState(state => ({ hasError: !state.selected }));
}
render() {
const { classes } = this.props;
const { selected, hasError } = this.state;
return (
<form className={classes.root} autoComplete="off">
<FormControl className={classes.formControl} error={hasError}>
<InputLabel htmlFor="name">
Name
</InputLabel>
<Select
name="name"
value={selected}
onChange={event => this.handleChange(event.target.value)}
input={<Input id="name" />}
>
<MenuItem value="hai">Hai</MenuItem>
<MenuItem value="olivier">Olivier</MenuItem>
<MenuItem value="kevin">Kevin</MenuItem>
</Select>
{hasError && <FormHelperText>This is required!</FormHelperText>}
</FormControl>
<button type="button" onClick={() => this.handleClick()}>
Submit
</button>
</form>
);
}
}
CodeSandBox 上的工作演示
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