Javascript 如何使用react refs设置背景图像?
我想使用react ref为某个div设置一个背景,以下是我迄今为止尝试的内容: 类组件:Javascript 如何使用react refs设置背景图像?,javascript,reactjs,Javascript,Reactjs,我想使用react ref为某个div设置一个背景,以下是我迄今为止尝试的内容: 类组件: import React from 'react'; import PropTypes from 'prop-types'; import classnames from 'classnames'; export default class CalendarDay extends React.Component { constructor(props) { super(props
import React from 'react';
import PropTypes from 'prop-types';
import classnames from 'classnames';
export default class CalendarDay extends React.Component {
constructor(props) {
super(props);
this.backgroundImageRef = React.createRef();
}
render () {
let { day, isToday, events, onClick } = this.props;
const dayClasses = classnames({
'flexColumn': true,
'day': true,
'inactive': day.siblingMonth,
'today': isToday,
});
if(typeof day.eventSlots !== 'undefined' && day.eventSlots.length > 0 ) {
let getEventData = Object.values(day.eventSlots)[0].eventClasses;
switch (getEventData) {
case 'event1':
let getInnerGrid = this.backgroundImageRef.current;
console.log(getInnerGrid); // returns null
//event1.style.backgroundImage = "url('../images/eventbg1.svg')";
console.log(getEventData);
break;
default:
break;
}
}
return (
<div
onClick={onClick.bind(null, this, day)}
className={dayClasses}>
<div ref={this.backgroundImageRef} className="inner-grid">
<div className="date">
{day.day}
</div>
{events}
</div>
</div>
);
}
}
CalendarDay.propTypes = {
day: PropTypes.object.isRequired,
isToday: PropTypes.bool,
events: PropTypes.array,
onClick: PropTypes.func,
};
从“React”导入React;
从“道具类型”导入道具类型;
从“类名称”导入类名称;
导出默认类CalendarDay扩展React.Component{
建造师(道具){
超级(道具);
this.backgroundImageRef=React.createRef();
}
渲染(){
让{day,isToday,events,onClick}=this.props;
const dayClasses=类名({
“flexColumn”:是,
“day”:没错,
“非活动”:天。同级月份,
"今天":,
});
if(typeof day.eventSlots!=“未定义”&&day.eventSlots.length>0){
让getEventData=Object.values(day.eventSlots)[0].EventClass;
开关(getEventData){
案例“事件1”:
让getInnerGrid=this.backgroundImageRef.current;
console.log(getInnerGrid);//返回null
//event1.style.backgroundImage=“url('../images/eventbg1.svg')”;
console.log(getEventData);
打破
违约:
打破
}
}
返回(
{day.day}
{events}
);
}
}
CalendarDay.propTypes={
日期:PropTypes.object.isRequired,
isToday:PropTypes.bool,
事件:PropTypes.array,
onClick:PropTypes.func,
};
现在,当我运行应用程序并检查控制台时,我看到空值。我做错了什么?您可以创建一个
bgStyle
,并根据条件更新bgStyle-based。然后你可以直接使用ondiv
作为样式道具
let bgStyle = {}
if(typeof day.eventSlots !== 'undefined' && day.eventSlots.length > 0 ) {
let getEventData = Object.values(day.eventSlots)[0].eventClasses;
switch (getEventData) {
case 'event1':
bgStyle.backgroundImage = "url('../images/eventbg1.svg')"
break;
default:
break;
}
}
return (
<div style={bgStyle} className="inner-grid">
<div className="date">
{day.day}
</div>
{events}
</div>
);
让bgStyle={}
if(typeof day.eventSlots!=“未定义”&&day.eventSlots.length>0){
让getEventData=Object.values(day.eventSlots)[0].EventClass;
开关(getEventData){
案例“事件1”:
bgStyle.backgroundImage=“url('../images/eventbg1.svg')”
打破
违约:
打破
}
}
返回(
{day.day}
{events}
);
您可以创建bgStyle
,并根据条件更新bgStyle。然后你可以直接使用ondiv
作为样式道具
let bgStyle = {}
if(typeof day.eventSlots !== 'undefined' && day.eventSlots.length > 0 ) {
let getEventData = Object.values(day.eventSlots)[0].eventClasses;
switch (getEventData) {
case 'event1':
bgStyle.backgroundImage = "url('../images/eventbg1.svg')"
break;
default:
break;
}
}
return (
<div style={bgStyle} className="inner-grid">
<div className="date">
{day.day}
</div>
{events}
</div>
);
让bgStyle={}
if(typeof day.eventSlots!=“未定义”&&day.eventSlots.length>0){
让getEventData=Object.values(day.eventSlots)[0].EventClass;
开关(getEventData){
案例“事件1”:
bgStyle.backgroundImage=“url('../images/eventbg1.svg')”
打破
违约:
打破
}
}
返回(
{day.day}
{events}
);
为什么要使用ref而不是样式
道具?请分享一个小演示。这将有助于调试更多内容。@NicholasTower我如何在这里使用style道具?您可以通过代码显示它吗?为什么要使用ref而不是style
道具?您可以分享一个小演示吗。这将有助于调试更多内容。@NicholasTower我如何在这里使用style prop?您可以通过代码显示它吗?