reactjs组件实例三大属性之refs使用示例：字符串形式的ref、回调函数形式的ref、回调ref中回调执行次数的问题

深藏阁楼爱情的钟 2023-10-02 18:07 5阅读 0赞

### 1\_字符串形式的ref ###

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>1_字符串形式的ref</title>
    </head>
    <body>
    	
    	<div id="test"></div>
    	
    	
    	<script type="text/javascript" src="../js/react.development.js"></script>
    	
    	<script type="text/javascript" src="../js/react-dom.development.js"></script>
    	
    	<script type="text/javascript" src="../js/babel.min.js"></script>
    
    	<script type="text/babel">
    		//创建组件
    		class Demo extends React.Component{
          
    			//展示左侧输入框的数据
    			showData = ()=>{
          
    				const {
          input1} = this.refs
    				alert(input1.value)
    			}
    			//展示右侧输入框的数据
    			showData2 = ()=>{
          
    				const {
          input2} = this.refs
    				alert(input2.value)
    			}
    			render(){
          
    				return(
    					<div>
    						<input ref="input1" type="text" placeholder="点击按钮提示数据"/> 
    						<button onClick={
          this.showData}>点我提示左侧的数据</button> 
    						<input ref="input2" onBlur={
          this.showData2} type="text" placeholder="失去焦点提示数据"/>
    					</div>
    				)
    			}
    		}
    		//渲染组件到页面
    		ReactDOM.render(<Demo a="1" b="2"/>,document.getElementById('test'))
    	</script>
    </body>
    </html>

![在这里插入图片描述][9506e9d75c674dabb528595446563eca.png]![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16]![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 1]

### 2\_回调函数形式的ref ###

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>2_回调函数形式的ref</title>
    </head>
    <body>
    	
    	<div id="test"></div>
    	
    	
    	<script type="text/javascript" src="../js/react.development.js"></script>
    	
    	<script type="text/javascript" src="../js/react-dom.development.js"></script>
    	
    	<script type="text/javascript" src="../js/babel.min.js"></script>
    
    	<script type="text/babel">
    		//创建组件
    		class Demo extends React.Component{
          
    			//展示左侧输入框的数据
    			showData = ()=>{
          
    				const {
          input1} = this
    				alert(input1.value)
    			}
    			//展示右侧输入框的数据
    			showData2 = ()=>{
          
    				const {
          input2} = this
    				alert(input2.value)
    			}
    			render(){
          
    				return(
    					<div>
    						<input ref={
          c => this.input1 = c } type="text" placeholder="点击按钮提示数据"/> 
    						<button onClick={
          this.showData}>点我提示左侧的数据</button> 
    						<input onBlur={
          this.showData2} ref={
          c => this.input2 = c } type="text" placeholder="失去焦点提示数据"/> 
    					</div>
    				)
    			}
    		}
    		//渲染组件到页面
    		ReactDOM.render(<Demo a="1" b="2"/>,document.getElementById('test'))
    	</script>
    </body>
    </html>

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 2]![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 3]

### 3\_回调ref中回调执行次数的问题 ###

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>3_回调ref中回调执行次数的问题</title>
    </head>
    <body>
    	
    	<div id="test"></div>
    	
    	
    	<script type="text/javascript" src="../js/react.development.js"></script>
    	
    	<script type="text/javascript" src="../js/react-dom.development.js"></script>
    	
    	<script type="text/javascript" src="../js/babel.min.js"></script>
    
    	<script type="text/babel">
    		//创建组件
    		class Demo extends React.Component{
          
    
    			state = {
          isHot:false}
    
    			showInfo = ()=>{
          
    				const {
          input1} = this
    				alert(input1.value)
    			}
    
    			changeWeather = ()=>{
          
    				//获取原来的状态
    				const {
          isHot} = this.state
    				//更新状态
    				this.setState({
          isHot:!isHot})
    			}
    
    			saveInput = (c)=>{
          
    				this.input1 = c;
    				console.log('@',c);
    			}
    
    			render(){
          
    				const {
          isHot} = this.state
    				return(
    					<div>
    						<h2>今天天气很{
          isHot ? '炎热':'凉爽'}</h2>
    						{
          /*<input ref={(c)=>{this.input1 = c;console.log('@',c);}} type="text"/><br/><br/>*/}
    						<input ref={
          this.saveInput} type="text"/><br/><br/>
    						<button onClick={
          this.showInfo}>点我提示输入的数据</button>
    						<button onClick={
          this.changeWeather}>点我切换天气</button>
    					</div>
    				)
    			}
    		}
    		//渲染组件到页面
    		ReactDOM.render(<Demo/>,document.getElementById('test'))
    	</script>
    </body>
    </html>

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 4]

### 4\_createRef的使用 ###

<!DOCTYPE html>
    <html lang="en">
    <head>
    	<meta charset="UTF-8">
    	<title>4_createRef</title>
    </head>
    <body>
    	
    	<div id="test"></div>
    	
    	
    	<script type="text/javascript" src="../js/react.development.js"></script>
    	
    	<script type="text/javascript" src="../js/react-dom.development.js"></script>
    	
    	<script type="text/javascript" src="../js/babel.min.js"></script>
    
    	<script type="text/babel">
    		//创建组件
    		class Demo extends React.Component{
          
    			/* 
    				React.createRef调用后可以返回一个容器，该容器可以存储被ref所标识的节点,该容器是“专人专用”的
    			 */
    			myRef = React.createRef()
    			myRef2 = React.createRef()
    			//展示左侧输入框的数据
    			showData = ()=>{
          
    				alert(this.myRef.current.value);
    			}
    			//展示右侧输入框的数据
    			showData2 = ()=>{
          
    				alert(this.myRef2.current.value);
    			}
    			render(){
          
    				return(
    					<div>
    						<input ref={
          this.myRef} type="text" placeholder="点击按钮提示数据"/> 
    						<button onClick={
          this.showData}>点我提示左侧的数据</button> 
    						<input onBlur={
          this.showData2} ref={
          this.myRef2} type="text" placeholder="失去焦点提示数据"/> 
    					</div>
    				)
    			}
    		}
    		//渲染组件到页面
    		ReactDOM.render(<Demo a="1" b="2"/>,document.getElementById('test'))
    	</script>
    </body>
    </html>

![在这里插入图片描述][watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 5]

[9506e9d75c674dabb528595446563eca.png]: https://img-blog.csdnimg.cn/9506e9d75c674dabb528595446563eca.png
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/73b6223dc8e34e8d9b5dd43ddaea263d.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 1]: https://img-blog.csdnimg.cn/4426b42d5d7f4eb2a40a1424d772115e.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 2]: https://img-blog.csdnimg.cn/0ea791e53bc04c31babea292cce40bbc.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 3]: https://img-blog.csdnimg.cn/d158c5693ed64a38880f6a6009140518.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 4]: https://img-blog.csdnimg.cn/6e11d752f39449ba839ff47fb4aaef11.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16
[watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w_size_20_color_FFFFFF_t_70_g_se_x_16 5]: https://img-blog.csdnimg.cn/c431d8a5fa734ea8aef8ee128bad0719.png?x-oss-process=image/watermark,type_d3F5LXplbmhlaQ,shadow_50,text_Q1NETiBA5a2m5Lqu57yW56iL5omL6K6w,size_20,color_FFFFFF,t_70,g_se,x_16