React 属性和状态的一些总结
一、属性
1、第一种使用方法:键值对
<ClaaNameA name = “Tom” />
<ClaaNameA name = {Tom} />
<ClaaNameA name = {“Tom”} />
<ClaaNameA name = {[1,2,3]} />//数组
<ClaaNameA name = {FunctionNAme} /> //定义一个函数
2、第二种方法:三个点的展开对象形式
var props = {
one :”123”,
tow :321
}
<ClassNameB {…props} />
增加三个引号相当于这里面拿到两个属性了(one和two)
3、setProps形式:通过组件更新属性,不能在组件内部中修改属性的,因为会违背组件设计原则(尽量避免)
var instance =React.render(<ClassNameC ><ClaasNameC/>,document.body);
instance.setProps({name:”Tom" });
二、状态:事物所处的状况,由事物自行处理不断变化/事物的私有属性
getInitialState:初始化每个实例特有的状态
setState:更新组件状态
setState会触发diff算法:判断state和页面结果的区别,是否需要更新
三、状态和属性对比
状态和属性都会触发render更新,都是纯JS对象
状态:是和自己相关的,既不受父组件也不受子组件影响
属性:本身是不能自己去修改的,只能从父组件获取属性,父组件也能修改它的属性
根本的区别:组件在运行时需要去修改维护的就是状态
四、简单的demo熟悉一下:
1 <!DOCTYPE html> 2 <html> 3 <head> 4 <meta http-equiv='Content-type' content='text/html; charset=utf-8'> 5 <title>daomul's example</title> 6 <link rel="stylesheet" href="../shared/css/base.css" /> 7 </head> 8 <body> 9 <h1>Text demo</h1> 10 <div id="container"> 11 12 </div> 13 14 <script src="../shared/thirdparty/es5-shim.min.js"></script> 15 <script src="../shared/thirdparty/es5-sham.min.js"></script> 16 <script src="../shared/thirdparty/console-polyfill.js"></script> 17 <script src="../../build/react.js"></script> 18 <script src="../../build/JSXTransformer.js"></script> 19 <script type="text/jsx"> 20 21 //内容组件 22 var Content = React.createClass({ 23 getInitialState:function(){ 24 return { 25 inputText:'', 26 }; 27 }, 28 handleChange:function(event){ 29 this.setState({inputText:event.target.value}); 30 }, 31 handleClick:function(){ 32 console.log("props name is " + this.props.selectName + " \n and inputText is " + this.state.inputText); 33 }, 34 render:function(){ 35 36 return <div> 37 <textarea onChange = {this.handleChange} placeholder = "please input something!"></textarea> 38 <button onClick = {this.handleClick}>sumbit</button> 39 </div>; 40 }, 41 }); 42 43 //评论组件 44 var Comment = React.createClass({ 45 getInitialState:function(){ 46 return { 47 names:["Tom","Axiba","daomul"], 48 selectName:'', 49 }; 50 }, 51 handleSelect:function(){ 52 this.setState( 53 {selectName : event.target.value} 54 ); 55 }, 56 render:function(){ 57 var options = []; 58 //往options中添加子option 59 for (var option in this.state.names) { 60 options.push(<option value={this.state.names[option]}> {this.state.names[option]} </option>) 61 }; 62 return <div> 63 <Content selectName = {this.state.selectName}> 64 </Content> 65 <select onChange = {this.handleSelect}> 66 {options} 67 </select> 68 </div>; 69 }, 70 }); 71 72 //start render 73 React.render(<Comment></Comment>,document.body); 74 </script> 75 </body> 76 </html>