React表单详解

一、不可控组件和可控组件

不可控组件：<input type="text" defaultValue="HelloWorld"/>数据写死。

可控组件：<input type="text" defaultValue={this.state.value}/>

为什么组件要可控：

符合React的数据流

数据存储在state中，便于使用

便于对数据进行处理

不可控组件代码：

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <Meta charset="UTF-8">
    <title>表单详解</title>
</head>
<body>
<script src="./build/react.js"></script>
<script src="./build/JSXTransformer.js"></script>
<script type="text/jsx">
    /*var MyForm = React.createClass({  render:function () {  return <input type="text" defaultValue="HelloWorld!"/>  }  });*/   var MyForm = React.createClass({
        submitHandler:function (event) {
            event.preventDefault();
            var HelloTo = React.findDOMNode(this.refs.helloTo).value;alert(HelloTo);
        },render:function () {
            return <form onSubmit={this.submitHandler}>
                <input type="text" ref="helloTo" defaultValue="Hello World"/><br/>
                <button type="submit">Speak</button>
            </form>
        }
    });
    React.render(<MyForm></MyForm>,document.body  );
</script>
</body>
</html>

可控组件代码：

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <Meta charset="UTF-8">
    <title>表单详解</title>
</head>
<body>
<script src="./build/react.js"></script>
<script src="./build/JSXTransformer.js"></script>
<script type="text/jsx">
    var MyForm = React.createClass({
        getInitialState:function () {
            return{
                helloTo:"helloworld"  };
        },handleChange:function () {
            this.setState({
                helloTo:event.target.value  });
        },submitHandler:function (event) {
            event.preventDefault();
            alert(this.state.helloTo);
        },render:function () {
            return <form onSubmit={this.submitHandler}>
                <input type="text" value={this.state.helloTo} onChange={this.handleChange}/><br/>
                <button type="submit">Speak</button>
            </form>
        }
    });
    React.render(<MyForm></MyForm>,document.body  );
</script>
</body>
</html>

二、不同表单元素的使用

实例代码如下：

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <Meta charset="UTF-8">
    <title>表单详解</title>
</head>
<body>
<script src="./build/react.js"></script>
<script src="./build/JSXTransformer.js"></script>
<script type="text/jsx">
    var MyForm = React.createClass({
        getInitialState:function () {
            return{
                username:"",gender:"man",checked:true  };
        },handleUsernameChange:function () {
            this.setState({
                username:event.target.value  });
        },handleGenderChange:function (event) {
            this.setState({
                gender:event.target.value  });
        },handleCheckBoxChange:function (event) {
            this.setState({
                checked:event.target.checked  });
        },submitHandler:function () {
            event.preventDefault();
            console.log(this.state);
        },render:function () {
            return <form onSubmit={this.submitHandler}>
                <label htmlFor="username">请输入用户名:</label>
                <input id="username" type="text" value={this.state.username} onChange={this.handleUsernameChange}/><br/>
                <select value={this.state.gender} onChange={this.handleGenderChange}><option value="man">男</option>
                    <option value="woman">女</option></select>
                <br/>
                <label htmlFor="checkBox">同意用户协议:</label>
                <input id="checkBox" type="checkBox" value="agree" checked={this.state.checked} onChange={this.handleCheckBoxChange}/>
                <button type="submit">注册</button>
            </form>
        }
    });
    React.render(<MyForm></MyForm>,document.body  );
</script>
</body>
</html>

三、事件处理函数复用

onChange={this.handleChange1}

onChange={this.handleChange2}

onChange={this.handleChange3}

onChange={this.handleChange4}

...

最好的处理方式是：处理成一个onChange={this.handleChange}

(1)bind复用

handleChange:function(name,event){

...

}

{this.handleChange.bind(this,'input1')}

实例代码如下：

handleChange:function (name,event) {
          var newState = {};
          newState[name] = name == "checked"?event.target.checked:event.target.value;
          this.setState(newState);
        },submitHandler:function (event) {
            event.preventDefault();
            console.log(this.state);
        },render:function () {
            return <form onSubmit={this.submitHandler}>
                <label htmlFor="username">请输入用户名:</label>
                <input id="username" type="text" value={this.state.username} onChange={this.handleChange.bind(this,"username")}/><br/>
                <select value={this.state.gender} onChange={this.handleGenderChange}><option value="man">男</option>
                    <option value="woman">女</option></select>
                <br/>
                <label htmlFor="checkBox">同意用户协议:</label>
                <input id="checkBox" type="checkBox" value="agree" checked={this.state.checked} onChange={this.handleChange.bind(this,"checkBox")}/>
                <button type="submit">注册</button>
            </form>
        }
    });
    React.render(<MyForm></MyForm>,document.body  );
</script>
</body>
</html>

(2)name复用

handleChange:function(event){

var name = event.target.name

}

{this.handleChange}

实例代码如下：

handleChange:function (event) {
          var newState = {};
          newState[event.target.name] = event.target.name == "checked"?event.target.checked:event.target.value;
          this.setState(newState);
        },submitHandler:function (event) {
            event.preventDefault();
            console.log(this.state);
        },render:function () {
            return <form onSubmit={this.submitHandler}>
                <label htmlFor="username">请输入用户名:</label>
                <input name="username" id="username" type="text" value={this.state.username} onChange={this.handleChange}/><br/>
                <select name="gender" value={this.state.gender} onChange={this.handleGenderChange}><option value="man">男</option>
                    <option value="woman">女</option></select>
                <br/>
                <label htmlFor="checkBox">同意用户协议:</label>
                <input name="checked" id="checkBox" type="checkBox" value="agree" checked={this.state.checked} onChange={this.handleChange}/>
                <button type="submit">注册</button>
            </form>
        }
    });
    React.render(<MyForm></MyForm>,document.body  );
</script>
</body>
</html>

四、表单组件自定义

为什么要自定义表单组件：

内因：本身具有特殊性：样式统一、信息内聚、行为固定

外因：本质上是组件嵌套

不可控的自定义组件：

代码如下：

<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <Meta charset="UTF-8">
    <title>表单详解</title>
</head>
<body>
<script src="./react-0.13.2/react-0.13.2/build/react-with-addons.js"></script>
<script src="./react-0.13.2/react-0.13.2/build/JSXTransformer.js"></script>
<script type="text/jsx">
    var Radio = React.createClass({
        getInitialState: function () {
            return {
                value: this.props.defaultValue
            };
        },handleChange: function (event) {
            if (this.props.onChange) {
                this.props.onChange(event);
            }
            this.setState({
                value: event.target.value  });
        },render: function () {
            var children = {};
            var value = this.props.value || this.state.value;
            React.Children.forEach(this.props.children,function (child,i) {
                var label = <label>
                    <input type="radio" name={this.props.name} value={child.props.value} checked={child.props.value == value} onChange={this.handleChange} />
                    {child.props.children}
                    <br/>
                </label>;
                children['label' + i] = label;
            }.bind(this));
            return <span>{children}</span>;
        }
    });
    var MyForm = React.createClass({
        submitHandler: function (event) {
            event.preventDefault();
            alert(this.refs.radio.state.value);
        },render: function () {
            return <form onSubmit={this.submitHandler}>
                <Radio ref="radio" name="my_radio" defaultValue="B">
                    <option value="A">First Option</option>
                    <option value="B">Second Option</option>
                    <option value="C">Third Option</option>
                </Radio>
                <button type="submit">Speak</button>
            </form>;
        }
    });
    React.render(<MyForm></MyForm>,document.body);
</script>
</body>
</html>

可控组件，示例代码如下：

handleChange: function (event) {
            if (this.props.onChange) {
                this.props.onChange(event); }
            this.setState({
                value: event.target.value  });
        },i) {
                var label = <label>
                    <input type="radio" name={this.props.name} value={child.props.value} checked={child.props.value == value} onChange={this.handleChange} />
                    {child.props.children}
                    <br/>
                </label>;
                children['label' + i] = label;
            }.bind(this));
            return <span>{children}</span>;
        }
    });
    var MyForm = React.createClass({
        getInitialState: function () {
            return {my_radio: "B"};
        },handleChange: function (event) {
            this.setState({
                my_radio: event.target.value  });
        },submitHandler: function (event) {
            event.preventDefault();
            alert(this.state.my_radio);
        },render: function () {
            return <form onSubmit={this.submitHandler}>
                <Radio name="my_radio" value={this.state.my_radio} onChange={this.handleChange}>
                    <option value="A">First Option</option>
                    <option value="B">Second Option</option>
                    <option value="C">Third Option</option>
                </Radio>
                <button type="submit">Speak</button>
            </form>;
        }
    });
    React.render(<MyForm></MyForm>,document.body);
</script>
</body>
</html>

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