我正在创建一个React Js网站。在这里，我有一个带有2个选择字段的最低价格和最高价格的表格。我想在这两个字段上应用验证。因此，如果用户单击最低价格500，则最高价格应仅显示500上涨。我的react组件代码在下面可用。
import React, { Component } from 'react';
import { Form, FormGroup, Input } from 'reactstrap';
class MyForm extends Component {
constructor(props) {
super(props);
this.state = {
};
}
handleSearch(event) {
alert("Search button clicked");
event.preventDefault();
}
render() {
return (
<div>
<header className="headerbg d-flex">
<div className="container my-auto">
<div className="row">
<div className="offset-1 col-10 offset-lg-0 col-lg-4">
<div id="search-form-div" className="container">
<div className="row">
<div className="col-12 my-4">
<h3>Search</h3>
<Form onSubmit={this.handleSearch}>
<FormGroup>
<Input type="select" name="select3" id="select3">
<option selected disabled>Min Price</option>
<option value="0">0</option>
<option value="500">500</option>
<option value="1000">1000</option>
<option value="1500">1500</option>
<option value="2000">2000</option>
</Input>
</FormGroup>
<FormGroup>
<Input type="select" name="select4" id="select4">
<option selected disabled>Max Price</option>
<option value="0">0</option>
<option value="500">500</option>
<option value="1000">1000</option>
<option value="1500">1500</option>
<option value="2000">2000</option>
</Input>
</FormGroup>
<FormGroup>
<Input type="submit" name="search" id="search" className="btn btn-primary" value="Search" />
</FormGroup>
</Form>
</div>
</div>
</div>
</div>
</div>
</div>
</header>
</div>
);
}
}
export default MyForm;
希望您能理解我的代码。预先感谢。
答案 0 :(得分：0)
您需要在输入中添加onChange函数。然后在选择minValue输入时更新状态。如果这是最大值，则将所选值与状态中的minValue进行比较，并在小于
时拒绝它如果还是要做这种形式的话，我会做另一种逻辑。我将基于对minValue的选择动态地为maxValue创建选项列表。我只会显示大于最小值的值。我想这对用户来说更方便。
答案 1 :(得分：0)
推荐的方法（我可能还会添加一种更简洁的方法，是将选项值放置在数组中，您要声明该状态并在更改值时进行更改）。因此您的组件可能看起来像这样...
import React, { Component } from 'react';
import { Form, FormGroup, Input } from 'reactstrap';
const defaultValues = [
{ value: 0, text: 0, key: 1 },
{ value: 500, text: 500, key: 2 },
{ value: 1000, text: 1000, key: 3 },
{ value: 1500, text: 1500, key: 4 },
{ value: 2000, text: 2000, key: 5 }
];
const MIN_TITLE = { selected: true, disabled: true, text: 'Min Price' };
const MAX_TITLE = { selected: true, disabled: true, text: 'Max Price' };
class MyForm extends Component {
constructor(props) {
super(props);
this.state = {
minData: [MIN_TITLE, ...defaultValues],
maxData: [MAX_TITLE, ...defaultValues],
minValue: null,
maxValue: null
};
// This allows us to access the state inside the renderoptions function.
// Another way (if you want to ignore this line) is to write the renderOptions
// as renderOptions = data => {}
this.renderOptions = this.renderOptions.bind(this);
}
handleSearch(event) {
alert('Search button clicked');
event.preventDefault();
}
renderOptions(data) {
return data.map(datum => {
// this allows us to indicate whether we are selecting or disabling
const selected = datum.selected || false;
const disabled = datum.disabled || false;
return (
<option key={datum.key} value={datum.value} selected={selected} disabled={disabled}>
{datum.text}
</option>
);
});
}
// Writing your function so does not require the binding in the constructor
handleMinSelect = event => {
const value = event.target.value;
const newMaxValues = [];
defaultValues.forEach(datum => {
// I'm under the impression that reactstrap will change the value to string
if (datum.value >= Number.parseInt(value, 10)) {
newMaxValues.push(datum);
}
});
this.setState({
maxData: [MAX_TITLE, ...newMaxValues],
minValue: value
});
};
handleMaxSelect = event => {
const value = event.target.value;
this.setState({ maxValue: value });
};
render() {
// I'm stri
<div>
<header className="headerbg d-flex">
<div className="container my-auto">
<div className="row">
<div className="offset-1 col-10 offset-lg-0 col-lg-4">
<div id="search-form-div" className="container">
<div className="row">
<div className="col-12 my-4">
<h3>Search</h3>
<Form onSubmit={this.handleSearch}>
<FormGroup>
<Input
type="select"
name="select3"
id="select3"
value={this.state.minValue}
onChange={this.handleMinSelect}>
{this.renderOptions(this.state.minData)}
</Input>
</FormGroup>
<FormGroup>
<Input
type="select"
name="select4"
id="select4"
value={this.state.maxValue}
onChange={this.handleMaxSelect}>
{this.renderOptions(this.state.maxData)}
</Input>
</FormGroup>
<FormGroup>
<Input
type="submit"
name="search"
id="search"
className="btn btn-primary"
value="Search"
/>
</FormGroup>
</Form>
</div>
</div>
</div>
</div>
</div>
</div>
</header>
</div>;
}
}
export default MyForm;
基本上，主要的变化是
renderOptions 希望它可以帮助您