我正在尝试获取输入框的字符限制,但输入字段有默认值。
如果字符限制超过文本必须出现在0限制处(非弹出窗口)
如果我使用下面的代码,它不能很好地满足我的需求(假设默认值已经存在)。
我能知道如何包含默认值和设置为0的消息吗
class Company extends React.Component {
state = {
Title: this.props.selectedTable.Title,
chars_left: 50,
max_char:50
}
handleCharacterCount= (event) => {
const charCount = event.target.value.length;
const maxChar = this.state.max_char;
const charLength = maxChar - charCount;
this.setState({ chars_left: charLength });
//this.setState({sTitle: e.target.value});
}
render() {
return (
<div>
<textArea
type="text"
maxLength="50"
required
onChange={this.handleCharacterCount}
value={this.state.Title}/>
/>
<p>{this.state.chars_left}</p>
</div>
)
}
}
发布于 2018-06-09 03:14:49
你可以试试这个
state = {
Title: this.props.selectedTable.Title,
chars_left: 50 - this.props.selectedTable.Title.length,
max_char:50
}
handleCharacterCount= (event) => {
const charCount = event.target.value.length;
const maxChar = this.state.max_char;
const charLength = maxChar - charCount;
this.setState({ chars_left: charLength,Title: event.target.value })}
render() {
return (
<div>
<textArea
type="text"
maxLength="50"
required
onChange={this.handleCharacterCount}
value={this.state.Title}/>
/>
{
!this.state.chars_left &&
<p>text has to appear at 0 limit</p>
}
<p>{this.state.chars_left}</p>
</div>)}
https://stackoverflow.com/questions/50766294
复制相似问题