即使使用箭头函数作为类属性,我仍然需要使用bind方法,如下所示的代码。当我在构造函数中删除绑定时,控制台会显示错误“Warning: A component is changing an uncontrolled input of type text to be controlled.”,表单错误也不会显示出来。
class Contact extends Component {
constructor(props) {
super(props);
this.handleBlur = this.handleBlur(this);
}
handleBlur = evt => field => {
this.setState({
touched: { ...this.state.touched, [field]: true }
});
render() {
return(
<Form onSubmit={this.handleSubmit}>
<FormGroup row>
<Label htmlFor="firstname" md={2}>
First Name
</Label>
<Col md={10}>
<Input
type="text"
id="firstname"
name="firstname"
placeholder="First Name"
valid={errors.firstname === ""}
invalid={errors.firstname !== ""}
value={this.state.firstname}
onBlur={event => {
this.handleBlur("firstname");
}}
onChange={this.handleInputChange}
/>
<FormFeedback>{errors.firstname}</FormFeedback>
</Col>
</FormGroup>
</Form>
)
}